Save " Women and Tefillin "
Women and Tefillin
Part 1: The Mitzvah in general (in brief)

(ח) וּקְשַׁרְתָּ֥ם לְא֖וֹת עַל־יָדֶ֑ךָ וְהָי֥וּ לְטֹטָפֹ֖ת בֵּ֥ין עֵינֶֽיךָ׃
(8) And you shall bind them as a sign on your hand, and they shall be totafot between your eyes.
... וְכָל מִצְוַת עֲשֵׂה שֶׁהַזְּמָן גְּרָמָהּ, אֲנָשִׁים חַיָּבִין וְנָשִׁים פְּטוּרוֹת...
...For all positive, time-bound commandments, men are obligated and women are exempt
כֹּל מִצְוַת עֲשֵׂה שֶׁהַזְּמַן גְּרָמָא וְכוּ': ת"ר אֵיזוֹהִי מִצְוַת עֲשֵׂה שֶׁהַזְּמַן גְּרָמָא סוּכָּה וְלוּלָב שׁוֹפָר וְצִיצִית וְתְּפִלִּין
Which mitzvot are positive time-caused [commandments]? Succah and Lulav, Shofar and Tzitzit and Tefillin
(ג) נָשִׁים וַעֲבָדִים וּקְטַנִּים פְּטוּרִין מִקְּרִיאַת שְׁמַע וּמִן הַתְּפִלִּין, וְחַיָּבִין בִּתְפִלָּה וּבִמְזוּזָה, וּבְבִרְכַּת הַמָּזוֹן:
Women, slaves, and minors are exempt from reciting Shema and from [wearing] Tefillin and are obligated in [praying] Shemonah Esrei and in [putting up a] Mezuzah and in [saying] Birkat HaMazon.
Is there a relationship between the listed things these people are exempt from and obligated in?
Is there a relationship between the listed exemptions? Between the listed obligations?
Part 2: Treatment of Tefillin in Rabbinic Sources

בָּרִאשׁוֹנָה הָיוּ נוֹתְנִין אוֹתָן לַחֲבֵירֵיהֶן וְהָיוּ נוֹטְלִין אוֹתָן וּבוֹרְחִין. הִתְקִינוּ שֶׁיְּהוּ מַנִּיחִין בְּחוֹרִין. וּכְשֶׁאִירָע אוֹתוֹ מַעֲשֶׂה הִתְקִינוּ שֶׁיְּהֵא אָדָם נִכְנַס וְהֵן בְּיָדוֹ. רִבִּי יַעֲקֹב בַּר אָחָא בְשֵׁם רִבִּי זְעִירָא אָמַר וְהוּא שֶׁיְּהֵא בַּיּוֹם כְּדֵי לְלוֹבְשָׁן. אֲבָל אִם אֵין בַּיּוֹם כְּדֵי לְלוֹבְשָׁן אָסוּר. דְּלָכֵן מִצְוָה לֹא עָבֵיד בּוֹן. לָמָּה הוּא מְבַזֵּי לוֹן. מַייְשַׁא בַּר בְּרֵיהּ דְּרִבִּי יְהוֹשֻׁעַ בֶּן לֵוִי אָמַר מַאן דַּעֲבַד טַבָּאוּת עוֹשֶׂה לָהֶן כִּיס שֶׁל טֶפַח וְנוֹתְנָן עַל לִבּוֹ. מַה טַעַם שִׁוִּיתִי ײ֨ לְנֶגְדִּי תָמִיד. תַּמָּן אָֽמְרִין כָּל־שֶׁאֵינוֹ כֶאֱלִישָׁע בַּעַל כְּנָפַיִם לֹא יִלְבַּשׁ תְּפִילִין.
First they were giving them to others; these were taking them and fleeing. They decreed that one should put them in holes in the wall. When that incident happened, they decreed that a person should enter and keep them in his hand. Rebbi Jacob bar Aḥa in the name of Rebbi Zeïra said: but only if there is time left during the day to put them on again. But if there is no time left in the day to put them on, it is forbidden. For if he cannot perform a mitzwah with them, why should he degrade them? Maisha (Moses), grandson of R. Joshua ben Levi, said: He who wants to do it right, makes for them a pouch the size of a hand-breadth and puts them on his heart. What is the reason? (Ps. 16:8): “I put the Eternal always before me.” There they say: He who is not like Elisha of the bird’s wings should not put on tefillin.
א"ר יַנַּאי תְּפִילִּין צְרִיכִין גּוּף נָקִי כֶּאֱלִישָׁע בַּעַל כְּנָפַיִם
מַאי הִיא? אַבָּיֵי אָמַר שֶׁלֹּא יָפִיחַ בָּהֶן רָבָא אָמַר שֶׁלֹּא יִישַׁן בָּהֶן
Rabbi Yannai said Tefillin need a guf naki [in order to be worn], like Elisha the Winged One [had].
What is it? Abaye says not passing wind with them on, Rava says not sleeping with them on
Does the singling out of a model to wear tefillin mean that it used to be rare and restricted?
What is different between the Bavli and Yerushalmi?

Other than this standard of tefillin wearing, Elisha is only mentioned in one other place in the Talmud, elaborating on his name. Does it shed any light on why he was picked as the standard for tefillin wearing?

וְאַמַּאי קָרֵי לֵיהּ 'בַּעַל כְּנָפַיִם'? שֶׁפַּעַם אַחַת גָּזְרָה מַלְכוּת רוֹמִי הָרְשָׁעָה גְּזֵירָה עַל יִשְׂרָאֵל שֶׁכָּל הַמַּנִּיחַ תְּפִילִּין יְנַקְּרוּ אֶת מוֹחוֹ וְהָיָה אֱלִישָׁע מַנִּיחָם וְיוֹצֵא לַשּׁוּק רָאָהוּ קַסְדּוֹר אֶחָד רָץ מִפָּנָיו וְרָץ אַחֲרָיו וְכֵיוָן שֶׁהִגִּיעַ אֶצְלוֹ נְטָלָן מֵרֹאשׁוֹ וַאֲחָזָן בְּיָדוֹ אָמַר לוֹ מַה זֶּה בְּיָדְךָ אָמַר לוֹ כַּנְפֵי יוֹנָה פָּשַׁט אֶת יָדוֹ וְנִמְצְאוּ כַּנְפֵי יוֹנָה לְפִיכָךְ קוֹרִין אוֹתוֹ אֱלִישָׁע בַּעַל כְּנָפַיִם וּמַאי שְׁנָא כַּנְפֵי יוֹנָה מִשְּׁאָר עוֹפוֹת מִשּׁוּם דְּאִמְּתִיל כְּנֶסֶת יִשְׂרָאֵל לְיוֹנָה שֶׁנֶּאֱמַר (תְּהִלִּים סָח, יד) כַּנְפֵי יוֹנָה נֶחְפָּה בַכֶּסֶף וְגוֹ' מַה יּוֹנָה כְּנָפֶיהָ מְגִינּוֹת עָלֶיהָ אַף יִשְׂרָאֵל מִצְוֹת מְגִינּוֹת עֲלֵיהֶן:
And why was he called the 'Winged One'? Because once the wicked Roman government passed a law against Israel that anyone who wears Tefillin would have his brain gouged out. Now, Elisha would wear them and go out into the market. [On one occasion,] an officer saw him, [so] Elisha fled and [the officer] pursued him. As [the officer] caught up, [Elisha] took [the Tefillin] off his head and held them in his hand. [The officer] said to him, "What's in your hand?" [Elisha] answered, "A dove's wings". [He then] opened his hand and they found a dove's wings. Because of this they callled him Elisha the Winged One.
And why the wings of a dove rather than some other bird? Because the community of Israel is compared to a dove, as it says, "like the wings of a dove covered with silver"; just as the wings of a dove protect it, so too the mitzvot of Israel protect [them]
"לְמַעַן תִּהְיֶה תּוֹרַת ה' בְּפִיךָ" לָמָּה נֶאֱמַר? לְפִי שֶׁנֶּאֱמַר "וְהָיָה לָךְ לְאוֹת": שׁוֹמֵעַ אֲנִי אַף הַנָּשִׁים בַּמַּשְׁמָע? וְהַדִּין נוֹתֵן: הוֹאִיל וּמְזוּזָה מִצְוַת עֲשֵׂה וּתְפִילִּין מִצְוַת עֲשֵׂה, אִם לָמַדְתְּ עַל מְזוּזָה שֶׁהִיא נוֹהֶגֶת בַּנָּשִׁים כְּבַאֲנָשִׁים, יָכוֹל אַף תְּפִילִּין יִנְהֲגוּ בְּנָשִׁים כְּבַאֲנָשִׁים? ת"ל "לְמַעַן תִּהְיֶה תּוֹרַת ה' בְּפִיךָ"—לֹא אָמַרְתִּי אֶלָּא בְּמִי שֶׁהוּא חַיָּיב בְּתַלְמוּד תּוֹרָה. מִכָּאן אָמְרוּ הַכֹּל חַיָּיבִין בִּתְפִילִּין חוּץ מִנָּשִׁים וַעֲבָדִים.
מִיכַל בַּת כּוּשִׁי הָיְתָה מָנָחַת תְּפִילִּין, אִשְׁתּוֹ שֶׁל יוֹנָה הָיְתָה עוֹלָה לָרְגָלִים, טָבֵי עַבְדּוֹ שֶׁל רַבָּן גַּמְלִיאֵל הָיָה מַנִּיחַ תְּפִילִּין:
"וּלְזִכָּרוֹן בֵּין עֵינֶיךָ לְמַעַן תִּהְיֶה תּוֹרַת ה' בְּפִיךָ"—מִכָּאן אָמְרוּ כֹּל הַמַּנִּיחַ תְּפִילִּין כְּאִלּוּ קוֹרֵא בַּתּוֹרָה, וְכָל הַקּוֹרֵא בַּתּוֹרָה פָּטוּר מִן הַתְּפִילִּין.
“So that God’s teaching will be in your mouth.”—Why was this said? From the statement “It shall be for you a sign,” I might have thought that women are included [in the obligation to wear Tefillin]. It would be logical: given that mezuzah and Tefillin are both positive commandments, if mezuzah is gender blind ought not Tefillin also be gender blind? Therefore, the verse says: “So that God’s teaching will be in your mouth”—[to teach that Tefillin only applies] to one who is obligated in Torah study. This is the basis for saying that all are obligated in Tefillin except for women and slaves.
Michal bat Kushi used to put on Tefillin, Yonah’s wife used to make the festival pilgrimage, Tavi, Rabban Gamliel’s slave used to put on Tefillin.
“As a reminder between your eyes, so that God’s teaching will be in your mouth”—This is the basis for saying that all who put on tefillin are like Torah readers, and everyone who reads from the Torah is exempt from Tefillin.
What do you think of the connection between tefillin and talmud torah?
What do you think of those 3 examples being tied together?
נָשִׁים מִנְיַין (דְּבָרִים יא) "וְלִמַּדְתֶּם אוֹתָם אֶת בְּנֵיכֶם" - וְלֹא אֶת בְּנוֹתֵיכֶם. אֶת שֶׁהוּא חַיָּיב בת"ת חַיֵּיב בִּתְפִילִּין, נָשִׁים, שֶׁאֵינָן חַיָּיבוֹת בת"ת, אֵינָן חַיָּיבִין בִּתְפִילִּין. הֲתִיבּוֹן הֲרֵי מִיכַל בַּת כּוּשִׁי הָיְתָה לוֹבֶשֶׁת תְּפִילִּין, וְאִשְׁתּוֹ שֶׁל יוֹנָה הָיְתָה עוֹלָה לָרְגָלִים, וְלֹא מִיחוּ בְּיָדֶיהָ חֲכָמִים? ר' חִזְקִיָּה בֹּשֶׂם ר' אָבָהוּ "אִשְׁתּוֹ שֶׁל יוֹנָה הוּשְׁבָה, מִיכַל בַּת כּוּשִׁי מִיחוּ בְּיָדֶיהָ חֲכָמִים."
From where do we know that women [are exempt from Tefillin]? [It is written in (Deuteronomy 11)] 'And you should teach it to your sons' - [and this implies] not to your daughters. [So] one who is obligated to learn Torah is obligated [to wear] Tefillin, [but] women, who are not obligated to learn Torah, or not obligated [to wear] Tefillin. They objected, but [what about] Michal bat Kushi who wore Tefillin, and the wife of Yonah who went on the pilgrimage, and the Sages didn't protest? Rabbi Chizkiyah said, quoting Rabbi Abahu, "Yonah's wife returned and [as for] Michal bat Kushi, the Sages did protest".

אֶלָּא הַאי תַּנָּא הוּא דְּתַנְיָא מִיכַל בַּת כּוּשִׁי הָיְתָה מָנָחַת תְּפִילִּין וְלֹא מִיחוּ בָּהּ חֲכָמִים
This Tanna taught in a Baraita, "Michal bat Kushi wore Tefillin and the Sages did not protest"

How does this Yerushalmi compare to the Mekhilta above? Do you think there is significance to the differences?

Medieval Sources dealing with Women and Tefillin:

Sources that seem to permit women wearing tefillin:While reading, note their logic (or lack therof) for their position. What conclusions can you draw?

(ט)...נָשִׁים וַעֲבָדִים וּקְטַנִּים פְּטוּרִין מִן הַצִּיצִית מִן הַתּוֹרָה וּמִדִּבְרֵי סוֹפְרִים...וְנָשִׁים וְעַבְּדִי' שֶׁרָצוּ לְהִתְעַטֵּף בַּצִּיצִית מִתְעַטְּפִים בְּלֹא בְּרָכָה וְכֵן שְׁאָר מִצְוַת עֲשֵׂה שֶׁהַנָּשִׁים פְּטוּרוֹת מֵהֶן אִם רָצוּ לַעֲשׂוֹת אוֹתָן בְּלֹא בְּרָכָה אֵין מְמַחִין בְּיָדָן.
...Women, slaves and children are exempt from [the mitzvah of] tzitzit [both] from the Torah and from the Rabbis...but women and slaves who wish to wear tzitzit may wear [them] without a blessing, and so too for other mitzvot where women are exempt, if they wish to do them without a blessing, we do not protest.
שו"ת הרשב"א חלק א סימן קכג
וְהִסְכַּמְתִּי כְּדִבְרֵי מִי שֶׁאוֹמֵר שֶׁאִם רָצוּ עוֹשׂוֹת כֹּל מִצְוַת עֲשֵׂה וּמְבָרְכוֹת, מִמַּעֲשֵׂה דְּמִיכַל בַּת שָׁאוּל שֶׁהָיְתָה מָנָחַת תְּפִילִּין. דְּלֹא מִיחוּ בְּיָדָהּ, אֶלָּא כִּרְצוֹן חֲכָמִים עֲבַדָא, וּסְתָמָא דְמִילְּתָא כֵּיוָן דְּמִנַּחַתְּ, מְבָרֶכֶת.
Rashba, Teshuva 1:123
I agree with those who say that if they desire they can do all such mitzvot and recite the blessings, on the basis of Michal bat Shaul who used to wear Tefillin and they did not protest; indeed she did so in accordance with the will of the Sages and by the nature of the matter since she puts on Tefillin she makes the blessing

Mishna Torah extrapolates from tzitzit and the lack of any objections to women doing that to all other such commandments, while Rashba interprets the Gemara's explicit telling of lack of objection as approval. Is there a meaningful difference?

These two sources, along with the Bavli, give no hint of an objection to women wearing tefillin. Keep that in mind in viewing the sources of objection.

וּלְרַבִּי יְהוּדָה מִיחוּ מִפְּנֵי שֶׁצְּרִיכִי גּוּף נָקִי כֶּאֱלִישָׁע בַּעַל כְּנָפַיִם וְנָשִׁים אֵינָם נְקִיּוּת גּוּף וְלֹא נְקִיּוּת דַּעַת וּלְרַבָּנָן לֹא מִיחוּ וְלֹא הוֹדוּ לֵהּ לֹא הוֹדוּ שֶׁמָּא לֹא יִשְׁמְרוּ בָּהֶם יָפָה וְלֹא מִיחוּ דְּאֶפְשָׁר דְּכֵיוָן דְּהֶחֱזִיקוּ בְּמִצְוָתָן נִזְהָרוֹת בְּהֵן ...
According to Rabbi Yehuda, they protested it because tefillin require a guf naki like Elisha Ba’al Kenafayim (Shabbat 49a) and women have neither cleanliness of body nor cleanliness of mind. According to the sages, they neither protested [nor condoned it]. They did not condone because perhaps they [women] would not take care of them well, and they did not protest because perhaps, since they kept the mitzva regularly, they were careful with them.
'מיכַל בַּת כּוּשִׁי הָיְתָה מָנָחַת תְּפִילִּין'. בִּפְסִיקְתָּא [רַבָּתִי פכ"ב] דר' חִזְקִיָּה בֹּשֶׂם ר' אָבָהוּ אָמְרוּ ...מִיכַל בַּת כּוּשִׁי מִיחוּ בָּהּ חֲכָמִים...וְנִרְאֶה לְפָרֵשׁ דְּטַעֲמָא למ"ד דְּלָא הָוֵי רְשׁוּת, מִשּׁוּם דִּתְפִילִּין צְרִיכִין גּוּף נָקִי, וְנָשִׁים אֵין זְרִיזוֹת לִיזָּהֵר...
'Michal bat Kushi wore Tefillin'.
In the Pesikta (Rabbati PC"B) of Rabbi Chizkiyah, they quoted Rabbi Abahu as saying that...[in the case of] Michal bat Kushi, the Sages protested...
It would seem that, according to those [who rule that women] are not allowed [to wear Tefillin], the rationale is that wearing Tefillin requires guf naki, and women are not sufficiently careful ....
While neither of these sources forbid women to wear tefillin, they do give a potential rationale to such a position. Is it the same rationale? What are the different ways of interpeting a woman's ability being offered?
What is the difference in basis between the Ritvah and Tosafot?
תשב”ץ קטן (תלמיד מהר”ם, בשמו), ער
אֵין לִמְחוֹת בְּיָדָם מִלְּהִתְעַטֵּף בַּצִּיצִית וּלְבָרֵךְ עָלָיו דִּיכוֹלוֹת לְחַיֵּיב עַצְמָן כִּדְמוּכָח בְּקִדּוּשִׁין (דַּף לא) אׇמְנָם אֵין לָהֶן לְהַנִּיחַ תְּפִילִּין לְפִי שֶׁאֵינָן יוֹדְעוֹת לִשְׁמוֹר עַצְמָן בְּטָהֳרָה:
Tashbetz Katan (Student of Maharam, in his name), 21
One should not protest their [women’s] wrapping themselves in tzitzit and reciting a beracha on it because they can obligate themselves, as is proven in Kiddushin (31). But they should not lay tefillin because they do not know how to keep themselves in purity.
The Maharam is especially concerned with "guf naki" as regards tefillin, forbidding minors and young men from wearing tefillin as well (Tshuvot Maharam 1:142) in contradiction to talmudic law explicitly assuming the right of a father to buy tefillin for a minor (Sukkah 42a – see also Sukkah 26b). He also extends "guf naki" beyond hygiene and and includes improper thoughts as a disqualification.
In your experience, do you, or Orthodox men, or Orthodox teenagers take this kind of care with their tefillin, refraining from wearing it when they are unwell or unfocused?
(ג) כָּתַב הר"ם נָשִׁים פְּטוּרוֹת מִתְּפִלִּין מִפְּנֵי שֶׁהִיא מִצְוַת עֲשֵׂה שֶׁהַזְּמַן גָּרְמָה שֶׁהֲרֵי אֵין מַנִּיחִין אוֹתָן בְּשַׁבָּת וְיוֹם טוֹב וְאִם רָצוּ לְהַנִּיחַ אֵין שׁוֹמְעִין לָהֶן מִפְּנֵי שֶׁאֵינָן יוֹדְעוֹת לְשַׁמֵּר עַצְמָן בִּנְקִיּוּת <ע"פ> עַד פא...
The Maharam writes that women are exempt from Tefillin because it is a positive time-bound commandment, since we don’t wear it on Shabbat and Yom Tov. And if they want to wear it, we do not listen, because they don’t know how to keep themselves clean...
The Maharam is the first halakhic source to suggest that women should not wear tefillin. Here are two representations of his words. The Kol Bo version is the one that the Rema (below) cites and it is his representation that is the basis for forbidding women from wearing tefillin. As nobody has ever suggested that ritual purity was related to tefillin wearing elsewhere, and the gemara (above) uses "naki (clean)" as the qualification, it seems likely to be the correct reading.
Why do you think these people introduced this extra concern for women?
Are the Tashbetz Katan and Kol Bo based on the rationale provided by Tosfot, and they believe the version of the gemara that has the sages protesting Michal to be the correct one?
Or do they believe the women of their experience are less clean than the ones of the gemara?
What factors point to either answer? What are the implications of these potential answers?

The people who say that the Maharam is claiming that women are exposed to more dirty things than men, such as menstrual blood and children's waste, are not fitting the language of "they don't know how to keep themselves clean." Additionally, these people think that the word "purity" in some versions indicates a focused concern, neglecting the fact that the term is used in the context of men and tefillin in regular discussions of guf naki elsewhere. Additionally, these people give no basis to say that a bit of blood or fecal matter anywhere on the body is a barrier to tefillin. At most, Sukkah 26b and SA OH 40:6 say that the hands should be clean.

...עוֹד זֹאת דָּרַשְׁתִּי לָהֶם כִּי מָה שֶׁאָמְרוּ רַבּוֹתֵינוּ (שַׁבָּת מט, א) תְּפִילִּין צְרִיכִין גּוּף נָקִי כֶּאֱלִישָׁע בַּעַל כְּנָפַיִם שֶׁלֹּא יָשֵׁן וְשֶׁלֹּא יָפִיחַ בָּהֶם, זֶהוּ בְּאָדָם שֶׁמַּנִּיחָן כָּל הַיּוֹם כּוּלּוֹ כְּמִצְוָתָן פֶּן יִשְׁכָּחֵם עָלָיו וְיַעֲשֶׂה בָּהֶם דָּבָר שֶׁאֵינוֹ הָגוּן, אֲבָל בִּשְׁעַת תְּפִילָּה אֵין לָךְ רָשָׁע שֶׁלֹּא יְהֵא רָאוּי לִתְפִילִּין, קַל וָחוֹמֶר מִסֵּפֶר תּוֹרָה שֶׁהוּא מְקוּדָּשׁ יוֹתֵר שֶׁיֵּשׁ בּוֹ כֹּל הַתּוֹרָה כּוּלָּהּ וּבַתְּפִילִּין אֵין בּוֹ כִּי אִם אַרְבַּע פָּרָשִׁיּוֹת שֶׁהֵם בְּתוֹךְ עוֹר, וְהַכֹּל אוֹחֲזִין בְּסֵפֶר תּוֹרָה בִּשְׁעַת תְּפִילָּה שֶׁהַכֹּל יְכוֹלִין לְהִתְנַהֵג בְּטָהֳרָה בִּשְׁעַת תְּפִילָּה:
...This too I expounded for them, that what our sages said, that tefillin require a guf naki like Elisha Ba’al Kenafayim, is that one not sleep and should not pass gas in them, this is for a person who lays them all day long in accordance with their mitzva, lest he forget that they are on him and treat them improperly. But at the time of tefilla, there is no evil-doer who would not be fitting for tefillin, a fortiori from a Torah scroll which is more sanctified because it contains the entire Torah while tefillin only have the four portions, encased in leather. Everyone may hold a sefer Torah at the time of prayer, since everyone can conduct himself in purity at the time of prayer.
The Semag here is addressing the concern of men, that because the bar for guf naki is so high, perhaps they should not wear tefillin at all for fear of wearing them improperly. He assures them that tefillin may be worn during prayer, as prayer is a time of naturally being "clean" in the relevant sense.
Do you think he is making a descriptive statement that the people he knows have this different frame of mind and caution when praying, or is he making a claim about the power of prayer in general?
Post medieval interpretations:

ביאורי הגרא תפילין לח:ד
<וי"ל> וְיֵשׁ לוֹמַר דְּגַם הַגְּמָרָא <ס"ל> סְבִירָא לֵיהּ כֵּן, אֶלָּא לֹא הוּצְרְכוּ לַהֲבִיאוֹ אֶלָּא <מ"ד> מַאן דְּאָמַר דְּנָשִׁים חַיָּיבוֹת, וְדָחוּ לֵיהּ <דס"ל> דִּסְבִירָא לֵיהּ <כמ"ד> כְּמַאן דְּאָמַר רְשׁוּת וּמוּתָּרוֹת.
Biurei HaGra, Tefillin 38:4
And there are those who say that our [Babylonian] Gemara also holds [that we object to women who wear Tefillin], and it only cited [the Baraita about how the Sages didn't object to Michal] according to those who say that women are obligated [in wearing tefillin], and we rejected that [opinion and instead] rule like those that say that women have the option and are allowed [to do positive time-bound mitzvot].
Do you think the novelty of the opinion of the Gra is relevant?
Regardless, other halakhic decisors largely ignore his claim and focus on the factors laid out by the talmudic and medieval authorities below
...כָּתַב הַכֹּלְבּוֹ בְּשֵׁם הר"ם שֶׁאִם רָצוּ הַנָּשִׁים לְהַנִּיחַ תְּפִילִּין אֵין שׁוֹמְעִין לָהֶם מִפְּנֵי שֶׁאֵינָן יוֹדְעוֹת לִשְׁמוֹר עַצְמָן בִּנְקִיּוּת <עכ"ל> עַד כָּאן לְשׁוֹנוֹ. וּבְסֵפֶר <א"ח> אוֹרְחוֹת חַיִּים הִקְשָׁה עָלָיו מִדְּאָמְרִינַן <בר"פ> בְּרֹאשׁ פֶּרֶק הַמּוֹצֵא תְּפִילִּין (שָׁם) דְּמִיכַל בַּת כּוּשִׁי (<פִּי'> פֵּירוּשׁ שָׁאוּל) הָיְתָה מָנָחַת תְּפִילִּין וְלֹא מִיחוּ בָּהּ חֲכָמִים <ול"נ> וְלִי נִרְאֶה שֶׁטַּעַם הר"ם כְּמוֹ שֶׁכָּתְבוּ <הַתּוֹסְ'> הַתּוֹסָפוֹת דְּאִיתָא בִּפְסִיקְתָּא שֶׁמִּיחוּ בָּהּ חֲכָמִים וּפֵירְשׁוּ הֵם דְּטַעֲמָא מִשּׁוּם דִּתְפִילִּין צְרִיכִין גּוּף נָקִי וְנָשִׁים אֵין זְרִיזוֹת לִיזָּהֵר והר"ם רָצָה לָחוּשׁ לְדִבְרֵי הַפְּסִיקְתָּא: וְכָתַב עוֹד הַכֹּלְבּוֹ בְּשֵׁם הר"ם וְעַל הַבַּחוּרִים שֶׁשָּׁאַלְתָּ אֲשֶׁר מֵהִרְהוּרִים אֲפִילּוּ בִּשְׁעַת קְרִיאַת שְׁמַע לֹא יַנִּיחוּ תְּפִילִּין <וַאֲפִי'> וַאֲפִילּוּ חוֹלִי מֵעַיִם אָסוּר לְהַנִּיחָם וְכֹל שֶׁאֵינוֹ יָכוֹל לְשׇׁמְרָם שֶׁלֹּא יָפִיחַ בָּהֶם אָסוּר כָּל שֶׁכֵּן שֶׁלֹּא יְנַהֵג בָּהֶם קַלּוּת רֹאשׁ בְּתַאֲוַת נָשִׁים <עכ"ל> עַד כָּאן לְשׁוֹנוֹ וּתְמָהַנִי דְּהָא תַּנְיָא <בפ"ב> בְּפֶרֶק ב' דְּסוּכָּה (כו:) רַבִּי יוֹסֵי אוֹמֵר הַיְלָדִים לְעוֹלָם חוֹלְצִין מִפְּנֵי שֶׁרְגִילִים בְּטוּמְאָה <ופירש"י> וּפֵירוּשׁ רַשִׁ"י שֶׁרְגִילִים בְּטוּמְאָה <קס"ד> קָא סָלְקָא דַעְתָּךְ שֶׁמָּא יָרְאוּ קֶרִי שֶׁהַהִרְהוּר מָצוּי בָּהֶם וּמֻתְמָהּ תַּלְמוּדָא לֵימָא קָסָבַר רַבִּי יוֹסֵי בַּעַל קֶרִי אָסוּר לְהַנִּיחַ תְּפִילִּין אָמַר אַבַּיֵּי בִּילָדִים וּנְשׁוֹתֵיהֶם עִמָּהֶם עָסְקִינַן שֶׁמָּא יָבֹאוּ לִידֵי הֶרְגֵּל דָּבָר הֲרֵי בְּהֶדְיָא דְּמִשּׁוּם הִרְהוּר לָא מִיתְּסַר וְאֶפְשָׁר לוֹמַר דהר"ם מְפָרֵשׁ <דקס"ד> דְּקָסָלְקָא דַעְתָּךְ דְּמִפְּנֵי שֶׁרְגִילִים בְּטוּמְאָה הַיְינוּ שֶׁהֵן בַּעֲלֵי קְרָיִין וּבַעַל קֶרִי אָסוּר לְהַנִּיחַ תְּפִילִּין <ומשו"ה> וּמִשּׁוּם הָכִי מֻתְמָהּ דְּבַעַל קֶרִי וַדַּאי חַיָּיב בִּתְפִילִּין וּמִיהוּ בְּעוֹד שֶׁהֵם עָלָיו צָרִיךְ שֶׁלֹּא יְהַרְהֵר וְאִם אֵינוֹ יָכוֹל לְהַעֲמִיד עַצְמוֹ מִלְּהַרְהֵר בְּשָׁעָה שֶׁהֵן עָלָיו לֹא יַנִּיחַ וּבְסֵפֶר <א"ח> אוֹרְחוֹת חַיִּים כָּתוּב עַל הָא דהר"ם וְכֵן מַשְׁמַע מִיְּרוּשַׁלְמִי שֶׁמְּפָרֵשׁ גּוּף נָקִי מִמַּחְשָׁבָה רָעָה <עכ"ל> עַד כָּאן לְשׁוֹנוֹ וְלִי נִרְאֶה דָּאֵין לְפׇטְרָם מִמִּצְוַת תְּפִילִּין מִפְּנֵי כָּךְ אֶלָּא יֵשׁ לְכוֹפָם בִּדְבָרִים וְלִמְשׁוֹךְ לִבָּם לְיִרְאַת שָׁמַיִם כְּדֵי שֶׁיַּסִּיחוּ לִבָּם מִדִּבְרֵי הֲבַאי הַמַּזִּיקִים לַגּוּף וּלְנֶפֶשׁ וְיִפְנוּ לִבָּם לְקַבֵּל עֲלֵיהֶם עוֹל מַלְכוּת שָׁמַיִם: כָּתַב הָרֹא"שׁ דְּאִיתָא בְּסֵפֶר הָעִתִּים סוּמָא פָּטוּר מִן הַתְּפִילִּין וּמִן הַצִּיצִית דִּכְתִיב וּרְאִיתֶם אוֹתוֹ פְּרָט לְסוּמָא וְהוּא זַ"ל חָלַק עָלָיו וּכְתָב דְּלֵיתָא דּוֹרְאִיתֶם אוֹתוֹ בַּצִּיצִית הוּא דִּכְתִיב:
...The Kol Bo (21) writes in the name of the Maharam that if women wish to wear Tefillin, we do not listen to them, since they do not know how to keep themselves clean. The Orchot Chaim (Tefillin 3) challenged this [view] based on the Talmud in Eruvin 96a, where Michal bat Kushi (daughter of Saul) wore Tefillin and the rabbis did not rebuke her. To me, it seems that the view of the Maharam is like that quoted by Tosafot (sv michal), [based on the fact that] in the Pesikta the Sages did rebuke her. And they explained the reason for this is that Tefillin need a guf naki and women are not careful about such matters. And the Maharam [reached his conclusion because] he was concerned for the view of the Pesikta. The Kol Bo further wrote in the name of the Maharam: Regarding the young men about which you asked, who because of salacious thoughts do not wrap tefillin even during the recitation of the shema, and even people with intestinal pains are forbidden to wear them, and anyone who is unable to stop themselves from passing gas while in them is forbidden [to wear them], let alone that one should not wear them while in a state of frivolous thoughts from temptation by women. And I was astonished by what was taught in chapter two of Sukkah: Rabbi Yosei said that young men must always remove [their tefillin before sleeping] because they are accustomed to being impure. And Rashi taught on "they are accustomed to being impure": it might have entered your mind that they might see an emission because they often have thoughts that might lead to it. And the Gemara goes on to ask, let us say that Rabbi Yosei holds that a baal keri is prohibited from wearing tefillin? Abaye said: We are only dealing with young men whose wives are with them, since they might engage in relations. It is thus explicit that salacious thoughts do not prohibit [the wearing of tefillin]. And you can say that the Maharam explains that it might have entered your mind that because they are accustomed to being impure that it is the same as if they were baal keri, and a baal keri is prohibited from wearing tefillin. And due to this, it is astonishing that a baal keri is in fact obligated in tefillin. However, as long as he is wearing them, he must not have any salacious thoughts, and if he cannot prevent these thoughts when the tefillin are upon him, he should not wear them. In the Orchot Chayim it is written according to the Maharam, and so is it derived from the Yerushalmi, that guf naki is interpreted from evil thought. And to me it seems that they should not be exempt from the commandment of tefillin for this reason. Rather, they should be forced in these matters, and their hearts should be pulled toward fear of heaven so that their hearts should be distracted from worthless things that do damage to the body and the soul, and they should turn their hearts to accept upon themselves the yoke of the kingdom of heaven. The Rosh wrote that there is [an opinion] in Sefer Haitim that a blind person is exempt from tefillin and tzitzit, as it is written "and you shall see them" - this excludes blind people. And he of blessed memory disagreed with this, and wrote that there is no "and you shall see them" - this was written [only in reference] to tzitzit.
The Orchot Chayim also states the view of the Maharam, that guf naki includes the need for thoughts free from salacious content, does not extend to women as they apparently have no salacious thoughts. He also quotes elsewhere, without qualification, that Rashbag was of the opinion that women may wear tefillin and say the relevant blessing.
Look back at the Kol Bo. Do you agree with Yosef Karo's description of its basis? Why would it matter?
What do you think of the Beit Yosef's approach to improper thoughts?
(ב) מצותן להיותם עליו כל היום אבל מפני שצריכי' גוף נקי שלא יפיח בהם ושלא יסיח דעתו מהם ואין כל אדם יכול ליזהר בהם נהגו שלא להניחם כל היום ומ"מ צריך כל אדם ליזהר בהם להיותם עליו בשעת ק"ש ותפלה:
(ג) קטן היודע לשמור תפילין בטהר' שלא יישן בהם ולא יפיח בהם: הגה ושלא ליכנס בהן לבית הכסא [רש"י פ' לולב הגזול] חייב אביו לקנות לו תפילין לחנכו: הגה וי"א דהאי קטן דוקא שהוא בן י"ג שנים ויום א' [בעל העיטור] וכן נהגו ואין לשנות [דברי עצמו]:
(2) It is a Mitzvah to have them [tefillin] on all day, but because they [tefillin] need a clean body [meaning that] he does not pass gas, and [further require] that one not distract his mind from them, and not every person is able to be careful with them, the practice is not to wear them all day. Nevertheless everyone needs to be careful with them when they are on during the reciting of Shema and Tefilah [aka Shemoneh Esreh] [because we concentrate on holy things at those times anyway].
(3) A minor who knows to guard tefillin in purity, such that he will not sleep or flatulate in them -Rema: "and not to enter the bathroom with them" (based on Rashi in the chapter of "The Stolen Lulav") - his father is obligated to acquire tefillin for him and train him [in the commandment]. Rema: "And some say that this 'minor' is only if he is 13 years and one day (Ba’al HaItur). And so is the custom and one should not change from it.
Why are tefillin and tefillah connected here?
What is the difference between the SA and Rema regarding minors?

Tefillin and prayer are connected, because the SA uncontroversially declares that a guf naki is essential to prayer (see next source) and it is at that time that men can be confident in their qualification to wear tefillin. Presumably the requirement for guf naki for prayer applies to women too, as he does not distinguish between them, and women were expected (required) to pray.

(ב) מִי שֶׁבָּרִי לוּ שֶׁאֵינוֹ יָכוֹל לְהִתְפַּלֵּל בְּלֹא הֲפָחָה מוּטָב שֶׁיַּעֲבוֹר זְמַן הַתְּפִלָּה מִמָּה שֶׁיִּתְפַּלֵּל בְּלֹא גּוּף נָקִי. (וְעַיֵּין לְקַמָּן סִימָן פ'). וְאִם יֵרָאֶה לוֹ שֶׁיּוּכַל לְהַעֲמִיד עַצְמוֹ בְּגוּף נָקִי בִּשְׁעַת קְרִיאַת שְׁמַע יַנִּיחַ תְּפִילִּין בֵּין אַהֲבָה לִקְרִיאַת שְׁמַע וִיבָרֵךְ:
(ג) נָשִׁים וַעֲבָדִים פְּטוּרִים מִתְּפִילִּין מִפְּנֵי שֶׁהוּא מִצְוַת עֲשֵׂה שֶׁהַזְּמַן גְּרָמָא.
הַגֵּה: וְאִם הַנָּשִׁים רוֹצִין לְהַחְמִיר עַל עַצְמָן מוֹחִין בִּידַן (כֹּל בּוֹ):
(ד) הַמַּנִּיחַ תְּפִילִּין צָרִיךְ לִיזָּהֵר מֵהִרְהוּר תַּאֲוַת אִשָּׁה.
הַגֵּה: וְאִם אִי אֶפְשָׁר לוֹ בְּלֹא הִרְהוּרִים מוּטָב שֶׁלֹּא לְהַנִּיחָם (כֹּל בּוֹ וְאוֹרְחוֹת חַיִּים):
(2) For one who is sure that they will not be able to pray without flatulating, it is better that the proper time for prayer passes than pray without a guf naki (see below, section 90). And if they think they can maintain a guf naki for the duration of the Shema, they sould wear Tefillin from 'ahavah' [the blessing before the Shema] until the Shema and make the blessings.
(3) Women and slaves are exempt from Tefillin because it is a positive commandment which is caused by time. Rema: And if women want to be stringent for themselves, we protest against it (Kol Bo).
(4) One who wears Tefillin must careful with their thoughts about women.
Rema: And if they find it impossible to do so without such thoughts, it is better for them not to wear [Tefillin] (Kol Bo and Orchot Chaim)
Note that the SA says that tefillin should only be worn for as long as guf naki can be maintained, and no longer.
Note the language of the Rema in the third section. How does it compare to the prohibitive language of the Kol Bo? Is there a meaningful difference in the action of the women in question? Is there a meaningful difference in the reaction prescribed? How would you explain the differences you see?
Modern Interpretations:

ים של שלמה קיד פרק א ס סד

דלא מיחו במיכל, לפי שהיתה צדקת גמורה, והיתה אשת מלך, גם לא היה לה ולד, והיתה יכולה לשמור עצמה בנקיות, מה שאין כן בשאר נשים

Yam Shel Shelomo, Kiddushin, 1:64

They did not protest Michal because she was a totally righteous woman, and the wife of a king, also she had no offspring, and she was able to keep herself in cleanliness, which is not so for other women.

Modern interpretations of some of these factors include:

  • Hygiene (NB: See discussion above for why physical hygiene is an uncompelling read of the earlier material)
    • Her royal status afforded her greater access to water and other hygienic amenities
    • Not having children would help avoid the hygienic issues of childcare
    • Not having children might reflect a biological reality of no menstruation (see Olat HaTamid below)
  • Spiritual/mental
    • Not having children would help avoid the distracting elements of childcare
    • Not having children reflects the metaphysical identity of Michal's soul as masculine
עולת התמיד לח:ד
וְאִם הַנָּשִׁים רוֹצִין <וְכוּ'> וְכוּלֵּי: הַטַּעַם כָּתַב בְּכֹלְבּוֹ מִשּׁוּם שֶׁאֵינוֹ יוֹדַעַת לִשְׁמוֹר אֶת עַצְמָן בִּנְקִיּוּת <עכ"ל> עַד כָּאן לְשׁוֹנוֹ וַאֲנִי תָּמֵהַּ אִם כֵּן לְמַאי הִצְרִיכוּ בִּגְמָרָא פֶּרֶק מִי שַׁמִּיתוּ לְפָרֵשׁ מִפְּנֵי שֶׁהוּא מִצְוַת עֲשֵׂה שֶׁהַזְּמַן גְּרָמָא הַנָּשִׁים פּוֹטְרוֹת מִן הַתְּפִילִּין <ת"ל> תַּלְמוּד לוֹמַר דַּאֲפִילּוּ אִם רוֹצִים לְהַחְמִיר אִסּוּרִין לְהַנִּיחַ תְּפִילִּין, שֶׁהֲרֵי אֵינָן יָדַעְתָּ לְשׇׁמְרָם בְּטָהֳרָה! אֶלָּא וַדַּאי דְּלֵיתָא לְהַאי טַעְמָא לְפִי סוּגְיוֹת הַגְּמָרָא וְכֵן אָמְרִינַן <בר"פ> בְּרֹאשׁ פֶּרֶק הַמּוֹצֵא תְּפִילִּין דְּמִיכַל בַּת כּוּשִׁי הָיְתָה מָנָחַת תְּפִילִּין וְלֹא מִיחוּ בָּהּ חֲכָמִים <אע"ג> אַף עַל גַּב דְּבַפְּסִיקְתָּא א' לְהֵיפֶךְ דְּמִיחוּ בָּהּ חֲכָמִים <מ"מ> מִכָּל מָקוֹם אֲנַן אַגְּמָרָא דִּידַן סָמְכִינַן. מִיהוּ יֵשׁ לִדְחוֹת, הָא דְּלָא מְפָרֵשׁ גְּמָרָא הַטַּעַם זֶה מִשּׁוּם שֶׁרוֹצֶה לִיתֵּן טַעַם גַּם לַעֲבָדִים דִּפְטוּרוֹת וְאִי מִשּׁוּם טַעַם זֶה לְבַד הָיָה נִרְאֶה דַּעֲבָדִים חַיָּיבִים שֶׁהֲרֵי בְּוַדַּאי הֵם יוֹדְעִים לְשׇׁמְרָם בְּטָהֳרָה וּלְפִיכָךְ מְפָרֵשׁ מִפְּנֵי שֶׁהוּא מִצְוַת עֲשֵׂה שֶׁהַזְּמַן גְּרָמָא • <דמש"ה> דְּמִשּׁוּם הָכִי גַּם עֲבָדִים פְּטוּרִים מִיהָא מֵהָא דְּאַמְּרֻנָּן דְּלֹא מִיחוּ בָּהּ חֲכָמִים מַשְׁמַע דְּאִם הָאִשָּׁה זְקֵנָה וְיָדְעִינַן בָּהּ שֶׁיּוֹדַעַת לִשְׁמוֹר אֶת עַצְמָהּ דָּאֵין לִמְחוֹת בָּהּ ובה"ג מַיְירֵי הָתָם:
Olat HaTamid 38:4
The Kolbo writes that the reason is because women do not know how to guard themselves with cleanliness. I was amazed at this, as if that is the case, why does the Talmud in chapter me shemeto need to explain that women are exempt from Tefillin because it is a time-caused positive commandment - Wouldn’t it be true [according to Kolbo] that even if they wish to be strict on themselves, it is prohibited for them to wear Tefillin since they do not know how to keep themselves clean! Rather, it must be that this reason [i.e., that women may not wear Tefillin due to cleanliness issues] is not correct according to the Talmudic text. So too, it says in the beginning of the chapter Hamotzee Tefillin that Michal Bat Shaul donned Tefillin and the Rabbis did not rebuke her; even though one Pesikta says the opposite, that they did rebuke her, nonetheless, we follow our Talmudic source. However, one could rebut the [previous] proof, [because perhaps] our Talmud [in me shemeto] does not give this explanation [cleanliness] since it wants to offer a reason why slaves are also exempt. And if it were for this reason [cleanliness] alone, it would appear that slaves are obligated in donning Tefillin, since they certainly know to keep themselves clean. Therefore the Talmud explains [that women are exempt from Tefillin] because of the principle of time bound positive commandments, since it is for this reason that slaves are also exempt. Nevertheless, the source that says the Rabbis did not rebuke Michal does imply that if a woman is elderly [i.e., post-menopausal] and we know that she is capable of watching herself [to stay clean], one should not rebuke her. And it is such a case that the Talmud has in mind there [i.e. in me shemeto, where women are said to be exempt from wearing Tefillin, not categorically forbidden from doing so].
Though this particular position of the Olat Tamid is not fully endorsed by many other Achronim, it is seemingly endorsed fully by the Mishna Brurah.https://seforimblog.com/2014/05/fixing-typesetting-error-in-order-to/
What do you think of his interpretation and rejection of the Kol Bo?
What is his defintion of guf naki as it applies to women?

The Maharshal and the Olat Tamid represent a new way of reading the central Talmudic source about Michal. All previous commentaries and halakhists viewed the Talmud as applying general principles about female performance of positive time bound commandments, or of tefillin in particular, to the specific case of Michal. These more modern authorities introduce the view that it is Michal who is exceptionally tolerated, while other women would be stopped. This view does not rely on the alternative Talmudic source of the rabbinic objection to Michal.

Further interpretations of Michal's uniqueness in this vein include: (Note that all the restrictive opinions of the post-medieval period are Ashkenazi. This did not stop some Achronim, even students of the Rema and Maharshal (e.g. Maset Binyamin 62) to permit women to wear tefillin)

  • She thought she was obligated in tefillin (Ma'ase Rokeach to SA OC 38)
  • She declared she would be careful with regards to guf naki (Shiltei HaGiborim 38:2)
  • Everyone recognized her, so she was not suspected of attempting to mix with men (Levush)
מגן אברהם לח:ג
"מוֹחִין כּוּ'" - מִפְּנֵי שֶׁצְּרִיכִין גּוּף נָקִי וְנָשִׁים אֵינָם זְרִיזוֹת לְהִזָּהֵר אֲבָל אִם הָיוּ חַיָּיבִים לֹא הָיוּ פְּטוּרִין <מה"ט> מֵהַאי טַעְמָא דְּהָוֵי רָמֵי אַנַּפְשַׁיְיהוּ וּמִזְדַּהֲרֵי <כַּנַ"ל> כַּנִּרְאֶה לִי דְּלָא <כע"ת> כְּעוֹלַת תָּמִיד
Magen Avraham 38:3
"We protest": Since they need a clean body and women are not particularly careful with cleanliness; but if they were obligated, they would not be exempt on that basis, since they would accept the mitzvah upon themselves and they would thus be conscientious. Such appears to me to be the rule, and not like the Olat Tamid.
What exactly is his disagreement with the Olat Tamid?
Pre Megadim (Mishbatzot 38:2), Arukh Hashulchan (38:6), and others read Magen Avraham as agreeing with the Olat Tamid that the prohibition of women wearing tefillin is only due to a caution that they are not careful. Magen Avraham offers as the rationale that women are not obligated and simply don't bother to be careful with their bodies for tefillin. His disagreement with the Olat Tamid is in his explicit rejection that women are inherently incapable of being careful enough to wear tefillin. Olat Tamid is the first source we have seen that implies directly that menstruation is a relevant factor in wearing tefillin, and it seems that Magen Avraham is rejecting the need for women to be both old and careful to wear tefillin, and just requires that women be careful.
(ו)... וְאִם רוֹצִין לְהַחְמִיר עַל עַצְמָן – מוֹחִין בִּידַן. וְלָא דָּמִי לְסוּכָּה וְלוּלָב שֶׁפְּטוּרוֹת וְעִם כׇּל זֶה מְבָרְכוֹת עֲלֵיהֶן. דְּכֵיוָן דִּתְפִילִּין צָרִיךְ זְהִירוּת יַתִּירָה מִגּוּף נָקִי, כִּדְאָמְרִינַן בְּשַׁבָּת (מט א): תְּפִילִּין צְרִיכִין גּוּף נָקִי כֶּאֱלִישָׁע בַּעַל כְּנָפַיִם. וּבַיְּרוּשַׁלְמִי בִּרְכוֹת שֵׁם אָמְרוּ: תַּמָּן אָמְרִין כֹּל שֶׁאֵינוֹ כֶּאֱלִישָׁע בַּעַל כְּנָפַיִם – אַל יַנִּיחַ תְּפִילִּין. אַךְ אֲנָשִׁים שֶׁמְּחוּיָּבִים – בְּהֶכְרֵחַ שֶׁיִּזָּהֲרוּ בָּהֶם בִּשְׁעַת קְרִיאַת שְׁמַע וּתְפִילָּה. וְלָכֵן אֵין מַנִּיחִין כֹּל הַיּוֹם, כְּמוֹ שֶׁכָּתַבְתִּי בְּסִימָן הַקּוֹדֵם. וְאִם כֵּן נָשִׁים שֶׁפְּטוּרוֹת, לָמָּה יַכְנִיסוּ עַצְמָן בַּחֲשָׁשׁ גָּדוֹל כָּזֶה? וְאֶצְלָן בִּשְׁעַת קְרִיאַת שְׁמַע וּתְפִילָּה כִּלְאָנְשִׁים כֹּל הַיּוֹם, לְפִיכָךְ אֵין מַנִּיחִין אוֹתָן לְהַנִּיחַ תְּפִילִּין. וְאַף עַל גַּב דְּתַנְיָא בְּעֵירוּבִין (צַו א) דְּמִיכַל בַּת שָׁאוּל הָיְתָה מָנָחַת תְּפִילִּין, וְלֹא מִיחוּ בָּהּ חֲכָמִים – אֵין לְמֵידִין מִזֶּה, דְּמִסְּתָמָא יָדְעוּ שֶׁהִיא צַדֶּקֶת גְּמוּרָה וְיָדְעָה לְהִזָּהֵר... (עַיֵּין מָגֵן אַבְרָהָם סְעִיף קָטָן ג' וּבֵית יוֹסֵף. וּלְפִי מַה שֶּׁכָּתַבְתִּי אָתֵי שַׁפִּיר.)
... If they want to be strict with themselves we protest. And it's not like Succah and Lulav where [women are also] exempt but they can [do them] and make blessings over them. [By contrast,] because Tefillin need more caution for guf naki, as we say in Shabbat (49a), "Tefillin need a guf naki like Elisha the Winged One". And in the Yerushalmi Brachot there they said: "Everyone who isn't like Elisha the Winged One should not wear Tefillin". But men, [since] they are obligated, are forced to be careful with them during the reading of the Shema and the Amidah. And therefore we don't wear them all day, as I wrote in the previous section. And according to this logic, [since] women are exempt, why would they take on this great risk? [Since] for them, the time [when they are] reading the Shema and the Amidah is comparable to the [rest of] the day for men, therefore they don't wear Tefillin. And even though it was taught in a Baraita in Eiruvin (96a) that Michal bat Shaul wore Tefillin, and the Sages didn't protest, we don't learn [the law] from that, since seemingly they knew that she was a complete tzadeket and knew to be cautious....(See Magen Avraham Section 3 and the Beit Yosef. And according to what I have written here it all makes sense)

Note that the Arukh Hashulchan describes wearing tefillin as very risky, and is ostensibly advocating for men to wear tefillin only to fulfill their obligation, and no longer. Given that the vast majority of men who wear tefillin do so for longer than just the Shema and Amidah, and before they are bar mitzvah, it is a bit disingenuous to apply his standard exactly.

The Arukh Hashulchan compares women's conscientiousness during prayer to men's outside of prayer. Elsewhere, he allows pious men who are conscientious about their bodies to wear tefillin outside of prayer and so seems to allow women who are careful to wear tefillin. He claims support for his position by the identifying of the objection for women to wear tefillin by the Beit Yosef as based on the Pesikta, and agree with the Beit Yosef in discarding it. He also claims support by the Magen Avraham's citing of caution as the factor that determines if anyone can wear tefillin including women.

Though the Arukh Hashulchan frames it as a rhetorical question, the sentiment of "since they are exempt, why would they take on the risk?" is a fair one that can be addressed. Additionally, it should be noted that he acknowledges the practice of particularly pious men to voluntarily assume the risk of voluntary wearing of tefillin, without the same rhetorical question.
Here is the Chatam Sofer describing some of the reasons why one might want to wear tefillin outside of an obligation. There are others, like Chabad, who attribute great symbolic (aligning thoughts and actions) and practical (winning the 6 Day War) power to the power of tefillin. Additionally, it is common for individuals to connect more to some mitzvot than others, and so stress them more, and it is generally regarded as a matter of taste.
חתם סופר, שבת מט.
יֵשׁ לְפָרֵשׁ עוֹבָדָא הָכִי, בְּשִׂים לֵב מַאי טַעְמָא הֵסִיר הַתְּפִילִּין מֵעָלָיו, הֲלֹא 'מִצְוָה בְּעִידָּנָא דַּעֲסִיק בָּהּ יוֹתֵר מַגְּנָא וּמְצִלָּה' (עִי' סוֹטָה כא.), וּמִכָּל שֶׁכֵּן תְּפִילִּין, דִּכְתִיב גַּבֵּיהּ (דְּבָרִים כח, י): "וְרָאוּ כׇּל עַמֵּי הָאָרֶץ כִּי שֵׁם ה' נִקְרָא עָלֶיךָ וְיָרְאוּ מִמֶּךָּ" (עִי' בְּרָכוֹת ו.) וְכוּ'. וְהַנִּרְאֶה שֶׁלְּפִי מש"כ רַבֵּינוּ יוֹנָה בְּשֵׁם הָרַמְבַּ"ם הֹל' תְּפִילִּין פ"ד הי"ד ט"ו, הוּבָא בָּרֹא"שׁ בְּהִלְכוֹת תְּפִילִּין (סִי' כא) שֶׁצְּרִיכִין גּוּף נָקִי שֶׁלֹּא יָקֵל רֹאשׁוֹ בָּהֶם...
Chatam Sofer, Shabbat 49a:
This requires explanation: What is the reason that we take Tefillin off [outside of prayers]; why, [Rav Yosef says in the Gemara] "When one is engaged in a mitzvah it protects and saves them" (see Sotah 21a). And even more so for Tefillin, with regards to which it is written (Deuteronomy 28:10): "Then all the nations of the world will see that you are called by the name of God and they will fear you" (see Brachot 6a). And it seems that according to what Rabbeinu Yonah wrote in the name of the Rambam in the Laws of Tefillin 4:14-15, as brought in the Rosh's Laws of Tefillin (Section 21), that they need guf naki, [meaning that] one should not be frivolous (lit. Light-headed) [when they are wearing] them...
תהילה לדוד לח:א
לְדַעַת הָרֹאשׁ זַ"ל שֶׁיִּתְבָּאֵר (סִי' פ' דִּתְפִילִּין) הַצְּרִיכוֹת גּוּף נָקִי וְכֵיוָן דְּנָשִׁים חַיָּיבוֹת בִּתְפִילָּה ע"כ דִּיכוֹלִין לִיזָּהֵר בִּשְׁעַת הַתְּפִילָּה מֵהַפָּחָה. וְגַם לְהָסֵךְ הַדַּעַת אֵין לָחוּשׁ בִּשְׁעַת הַתְּפִילָּה. דְּמִטַּעַם זֶה א"ל לְמַשְׁמֵשׁ בָּהֶם בִּשְׁעַת הַתְּפִילָּה כמ"ש המ"א בְּסִי' מ"ד ס"ק ב'. וא"כ יֵשׁ לְעַיֵּין אִי צָרִיךְ לִמְחוֹת בְּנָשִׁים כְּשֶׁרוֹצִין לְהַנִּיחָן בִּשְׁעַת הַתְּפִילָּה דְּאֶפְשָׁר דְּהָא שֶׁכָּתַב רַמָ"א זַ"ל בס"ג דְּמוֹחִין בְּיָדָם הָיִינוּ כְּשֶׁרוֹצִין לְהַנִּיחָן כֹּל הַיּוֹם וְעַיֵּין א"א ס"ק ג'
Tehilla l'David, Orach Chayyim 38:1
According to the Rosh who explains the need for a guf naki, since women are obligated in tefillah they are [clearly] able to be careful at a time of davening mehafacha. And similarly [with regards to the concern for] lacking concentration, there is no concern at a time of davening. From this reasoning, it's possible for them to touch them during prayer like the Magen Avraham says in Section 44, Sub-Section 2. And if so, there is room to investigate if one needs to object to women who want to wear [Tefillin] during prayers, for it is possible that [when] the Rema (Z"L) wrote in Section 3 that we protest, [this is only] when they want to wear [Tefillin] all day. And see AA, Sub-Section 3.
For information about the author of this work, see here.
What do you think about his reading of the Rema?
Contemporary sources:

Previously in this responsum, Rabbi Moshe Feinstein simply states that women cannot wear tefillin because it is forbidden, and does not elaborate. Below is his reasoning for women performing non-obligatory mitzvot, answering how the religious feminist movement, that is anti-Torah, should be addressed. His reasoning here is applied to tefillin by others later (see below)

אגרות משה ד:מט
...אֲבָל פָּשׁוּט שֶׁהוּא רַק בְּחִשְׁקָהּ נַפְשָׁהּ לְקַיֵּים מִצְוַת אַף כְּשֶׁלֹּא נִצְטַוְּותָה, אֲבָל מִכֵּיוָן שֶׁאֵינוֹ לְכַוָּונָה זוֹ אֶלָּא מִצַּד תּוֹרַעְמוֹתָהּ עַל <השי"ת> הַשֵּׁם יִתְבָּרַךְ וְעַל תּוֹרָתוֹ אֵין זֶה מַעֲשֵׂה מִצְוָה כְּלָל אֶלָּא אַדְּרַבָּה מַעֲשֵׂה אִיסּוּר שֶׁהָאִיסּוּר דִּכְפִירָה שֶׁחוּשַּׁבְתְּ דְּשָׁיֵיךְ שֶׁיִּהְיֶה אֵיזֶה חִלּוּף בְּדִינֵי הַתּוֹרָה הִיא עוּשֵּׂית גַּם בְּמַעֲשֵׂה שֶׁחֲמִיר.
Igerot Moshe, 4:49:
...However, it is obvious that this applies only if her soul yearns to perform mitzvot, notwithstanding the fact that she is not commanded to perform them. However, since it is not with this intent, but rather stems from her protest against God and God's Torah, this is not the act of a mitzvah at all; on the contrary, [it is] a forbidden act, since she commits heresy by thinking that it is possible for the laws of the Torah to be changed even in this weighty matter.
R' J. H. Henkin, Responsa on Contemporary Jewish Women's Issues p. 33
However, she should not lay Tefillin, as the poskim conclude in Orach Chayyim 38:3. Talmud Torah for women was permitted because it was necessary but Tefillin are not necessary, and she should strengthen her ties to Judaism through other means.

What is Rav Henkin's presumed motive for women who want to wear tefillin? How does it compare to such sources as Rav Moshe Fienstien or Chatam Sofer?

פניני הלכה, א:ט:יג:
לְמַעֲשֶׂה, הַהוֹרָאָה שֶׁלֹּא תַּנִּיחַ, וְרַבִּים כָּתְבוּ שֶׁיֵּשׁ לִמְחוֹת בְּיַד הָרוֹצוֹת לְהַנִּיחַ, וכ"כ הָרַמָ"א ומ"ב לַח, יג, וכה"ח לַח, ט, וְעוֹד רַבִּים. אֶלָּא שֶׁכְּפִי שֶׁכָּתַבְתִּי, לְרוֹצֶה לְהַנִּיחַ יֵשׁ עַל מָה לִסְמוֹךְ, שֶׁכָּךְ דַּעַת הָאוֹרְחוֹת חַיִּים וְעוֹלַת תָּמִיד, וְאַף מִסִּיּוּם דִּבְרֵי ערוה"ש מְבוֹאָר שֶׁאֵין לִמְחוֹת בְּמֵי שֶׁמְּפוּרְסֶמֶת כְּצַדֶּקֶת. וְלָכֵן לְמַעֲשֶׂה אֵין לִמְחוֹת בְּיָדָהּ. וּבִתְנַאי שֶׁתַּקְפִּיד שֶׁלֹּא תַּנִּיחַ בִּשְׁעַת וִסְתָּהּ. וְכֵן תַּקְפִּיד לְהַנִּיחַ בְּצִנְעָה, כִּי רַק כָּךְ יִהְיֶה בָּרוּר שֶׁהַנֶּחְתֶּה לְשֵׁם שָׁמַיִים, וְעוֹד שֶׁצָּרִיךְ לְהַצְנִיעַ אֶת זְמַנֵּי הַטׇּהֳרָה וְהַטּוּמְאָה.
Peninei Halakha, 1:9:13:
Practically speaking, the law is that they shouldn't wear [Tefillin], and many write that we should object to those who want to wear [Tefillin], and the Rema writes this as well as the M"B 38, 13, KH"C 38, 9, and many more. But as I have written, those who want to wear [Tefillin] have [lenient opinions] to rely upon, since there is the Orchot Chaim and the Olat Tamid, and even the ruling of the Aruch HaShulchaan explains that we don't object to [women wearing Tefillin] where it is known that they are righteous. And therefore, practically speaking, we don't object. But this is on condition that they are careful not to wear it during their period, and [likewise] that they are careful to only wear it in private, since only then will it be clear that they are wearing it for the sake of Heaven, and also because they need to be private with regards to their time of purity and impurity.
Note that the only objection he suggests for women wearing tefillin is their menstrual cycle and their motive, both modern objections.
Do you think the objectionable motive he has in mind is the same as Rav Moshe Feinstien? What effect does the phrasing change have?

I believe his objection of motive is based on Rav Moshe Fienstien's characterization of feminism. However, without specifying the motive, he makes it sound like there is no proper motive for wearing tefillin publicly, even if a constructive one (like wanting to daven with a minyan) can be easily imagined.

Rav Melamed also says that women are not allowed to reveal their purity status, but that is not a universally held practice in Orthodoxy. Much of Orthodoxy does not abide by this practice, and many say that it is at most minhag, and so communally dependant. (e.g. https://www.yoatzot.org/questions-and-answers/894/)

Letter from the Principal of SAR High School
Dear Parents,
The issue of women and Tefillin resurfaced this week in light of the Boiling Point article recently published at Shalhevet High School in Los Angeles and circulated on Facebook. It has since become an international topic of discussion. I imagine that many of you have read the articles and have had many conversations on the issue. Over the course of December, I spoke with students and faculty but I did not communicate directly with the parent body on the topic. Given the international publicity of this week, I would like to share my thoughts directly with you.
Two girls who have put on Tefillin since their bat mitzvah approached me months ago to ask permission to put on Tefillin in school. Both students, in their respective ways, have shown real commitment to this mitzvah. Since their bat mitzvah, they have been taught, in accordance with their family practice, to daven each day with Tefillin. For me, this was a question of whether I could allow a young woman to practice as she had been taught – to daven each and every day in a meaningful way wearing Tefillin as an expression of her עבודת השם. I felt that my responsibility was to consider the person before me and the halakha, before considering the political fallout of the decision.
In my opinion, the practice of these families has support in halakha. It has basis in the Rishonim (רמב״ם, רשב״א וספר החינוך) – and R. Yosef Karo, the מחבר שולחן ערוך, seems to follow that opinion. I felt it appropriate to see this as a legitimate practice albeit different than our communal practice – but one that has halakhic justification. As such, I granted the two girls permission in the context – in a tefilah setting – of a group of girls who were supportive of their practice. I felt it appropriate to create space at SAR for them to daven meaningfully. I explained this to our students in this way: it is a halakhically legitimate position despite it not being our common communal practice. But since there is support for it, I would be willing to create such space in the school. I did not, in so doing, create new policy nor invite any female student who wanted to don tefillin to do so. These are girls who, I believe, have been מוסר נפש (for a teen to get up at 6:20 each morning is meaningful commitment) for this מצוה. At its core, women donning Tefillin is a discretionary act in Jewish law. While our community has adopted as normative the view that women refrain from this act, I see the range of rishonim who allow women to don tefillin as support to give space to that practice within our community. One can disagree with this decision on halakhic and public policy grounds. But the position is a coherent one and deserves careful consideration.
But why? What was so important about this? As the weeks passed and I heard the various reactions and responses, my feelings on the issue became increasingly clear to me. Perhaps this is best expressed by way of a story. I daven in R. Yosef Adler’s shul, Congregation Rinat Yisrael, in Teaneck. Many of you know Rabbi Adler as the principal of TABC. On that day back in December when I emailed the faculty, I met Rabbi Adler at a community event. He crossed the room and came over to me, took my hand in his two hands and said, “yasher koach, you made the right decision. In a world where there are so many things that distract our teens from focusing on mitzvot, we should support teenagers who seek to strengthen their connection to Hashem and to a life of mitzvot. If I taught girls in my school, I would make the same decision.” In fact, as he subsequently shared with me, he had made the same decision. A few years back, a woman from the community asked if she could daven at the morning minyan at Rinat – but, she said, I wear tallis and tefillin when I daven. Rabbi Adler permitted her to daven in shul. A number of men in the community came over to him and said that they refused to daven in such a minyan. That story crystallized it all for me. I told my students (and I went to each of our four grades for a community meeting to explain the decision – as well as giving two faculty shiurim for staff) that I am not committed to the idea of SAR girls putting on tefillin. I am not encouraging our girls to do so. But I am committed to having our boys and girls be able to daven in the same shul where a woman might be doing so. That when they see something different, even controversial, before deciding in which denomination it belongs, they must first take a serious look at the halakha and ask their Rabbi whether there is basis for such practice. I suspect that I would not differ much regarding normative halakha with most people in our community. But I would differ strongly with someone who thought this was cause for that person to be removed from the community – or that such practice could not be supported within the community shul. I permitted our two female students to daven with tefillin because I believe that we should not be afraid of different forms of עבודת השם when there is halakhic argument to support it. I permitted the young women to daven with tefillin because we should be proud, as a Modern Orthodox community, that we recognize the sanctity and dignity of each person and we find ways to support their spiritual growth in different ways.
I am proud to say that many students have taken this as an opportunity to learn about their classmates and to learn the sources more carefully. They have engaged each other seriously and respectfully. They have helped shape an atmosphere of support, of care, of אהבת ישראל.
And here is what we do not do: we do not loosely and without basis malign other Jews, call them names, disparage their motivations and their divine service in the name of…what? I am not sure. I have been reading social media (a new practice for me) and I have been appalled. I have read people maligning these two fine young women with insults and false characterizations based on…nothing. It is awful; it is abominable; it is unacceptable. Two girls who are שומרי שבת וכשרות, גומלי חסד,and בנות תורה. It has been awful to watch. It is מוציא שם רע at its worst (of kids, no less). We should be proud to be stringent in recognizing the dignity of others and valuing their divine service and stringent about how we talk about others, especially children.
I know that not everyone agrees with my decision. I expect that and I respect that. It is my hope that we can champion, together, ahavat yisrael, love for each Jew; that we can come together as a community even when we disagree; that we can deeply respect each other with pride as we create space for us to work together, as a community, to strengthen ourselves in our עבודת השם.
With respect and appreciation,Rabbi Tully HarcsztarkPrincipal
SAR High School
Conclusions:
1. The original objections to women wearing tefillin had to do with the historical women specifically, and it is not contradicting all those sources to say that today's women are different. The vast majority of halakhists interpret the objection to women wearing tefillin to be not intrinsic or related to menstruation and therefore overcomeable. In this view, even Kol Bo, Rema, Magen Avraham, and others would be ok with today's motivated and careful women wearing tefillin
1.1. The historical objections to women wearing tefillin were more about the mental aspect of guf naki than the physical, with almost all the sources implying that blood is an irrelvant factor, with the Olat Tamid being the exception.
2. Even if those objections were ahistorical, there are many opinions to rely on to at least be tolerant of divergent practice, such as Mishneh Torah, Rashba, Shulchan Aruch, Tehillah l'David, Aruch Hashulchan
3. People who bar women from this mitzvah usually apply the fundamental objections inconsistently when it comes to men. For example, Chabad putting tefillin on people outside the context of prayer when either aspect of guf naki cannot be guaranteed, when these people are usually even more presumably lacking the proper intent and focus than women would be.