(ב) וַיְדַבֵּ֤ר מֹשֶׁה֙ אֶל־רָאשֵׁ֣י הַמַּטּ֔וֹת לִבְנֵ֥י יִשְׂרָאֵ֖ל לֵאמֹ֑ר זֶ֣ה הַדָּבָ֔ר אֲשֶׁ֖ר צִוָּ֥ה יְהֹוָֽה׃ (ג) אִישׁ֩ כִּֽי־יִדֹּ֨ר נֶ֜דֶר לַֽיהֹוָ֗ה אֽוֹ־הִשָּׁ֤בַע שְׁבֻעָה֙ לֶאְסֹ֤ר אִסָּר֙ עַל־נַפְשׁ֔וֹ לֹ֥א יַחֵ֖ל דְּבָר֑וֹ כְּכׇל־הַיֹּצֵ֥א מִפִּ֖יו יַעֲשֶֽׂה׃ (ד) וְאִשָּׁ֕ה כִּֽי־תִדֹּ֥ר נֶ֖דֶר לַיהֹוָ֑ה וְאָסְרָ֥ה אִסָּ֛ר בְּבֵ֥ית אָבִ֖יהָ בִּנְעֻרֶֽיהָ׃ (ה) וְשָׁמַ֨ע אָבִ֜יהָ אֶת־נִדְרָ֗הּ וֶֽאֱסָרָהּ֙ אֲשֶׁ֣ר אָֽסְרָ֣ה עַל־נַפְשָׁ֔הּ וְהֶחֱרִ֥ישׁ לָ֖הּ אָבִ֑יהָ וְקָ֙מוּ֙ כׇּל־נְדָרֶ֔יהָ וְכׇל־אִסָּ֛ר אֲשֶׁר־אָסְרָ֥ה עַל־נַפְשָׁ֖הּ יָקֽוּם׃
(2) Moses spoke to the heads of the Israelite tribes, saying: This is what יהוה has commanded:
(3) If a householder makes a vow to יהוה or takes an oath imposing an obligation on himself, he shall not break his pledge; he must carry out all that has crossed his lips. (4) If a woman makes a vow to יהוה or assumes an obligation while still in her father’s household by reason of her youth, (5) and her father learns of her vow or her self-imposed obligation and offers no objection, all her vows shall stand and every self-imposed obligation shall stand.
(1) AND MOSES SPOKE UNTO THE HEADS OF THE TRIBES. Scripture did not precede this section with [the statement]: “And the Eternal spoke unto Moses, saying: Speak unto the heads of the tribes, and say unto them: This is the thing which the Eternal hath commanded,” as He stated in the section [dealing with] slaughtering [offerings] outside the Sanctuary Court, and in other sections. Instead, He mentioned it as the end of this section, saying, These are the statutes, which the Eternal commanded Moses. . . . .
And Moses spoke unto the heads of the tribes. The reason [why he did not address this section to the entire people] is because it was not necessary to teach all the children of Israel that the father and husband [of a woman] can declare void those vows [of their daughter or wife, respectively] which involve affliction of the soul, and perhaps it is [even] necessary to conceal these [rights] from them, so that they should not treat vows lightly. But it was to the Sages of Israel, the heads of their tribes, that he taught the ordinance [of vows]. The verse also alludes to the interpretation of our Rabbis [who said] that the heads of the tribes have a special function and power in vows over and above the rest of the people, namely, that a single person who is an expert in the laws can release a person from a vow [and therefore, this section was addressed to the heads of the tribes, i.e., the Sages].
https://www.rabbisacks.org/covenant-conversation/matot/keeping-our-word/
Vows and oaths are obligations created by words. They are commitments to do something or refrain from doing something. A vow, neder, affects the status of an object. I may vow not to eat something. That something is now, for me, forbidden food. An oath, shevuah, affects the person not the object. What is now forbidden is not the food but the act of eating it. Both acts bind: that is the primary meaning of the word issar.
(א) או השבע שבעה לאסר אסר מה בין נדר לשבועה נדר נודר בחיי המלך שבועה נשבע במלך עצמו ואעפ״י שאין ראיה לדבר זכר לדבר חי ה׳ וחי נפשך אם אעזבך.
(1) או השבע שבועה לאסור איסר, “or swears an oath to declare something permitted to others as forbidden to himself;” what is the difference between making a “vow” and “swearing an oath,” seeing both place something out of bounds to the party making such a declaration? When making a vow the object of the vow is placed out of bounds to the party who makes such a vow, whereas when swearing an oath, the party swearing it places himself out of bounds to the object or people that are the subject of such an oath. Even though the Torah has not spelled this out specifically, we find hints that this is so in the wording used by the Torah to describe these two kinds of self imposed restrictions. (Compare Sifri) If someone says: “by the Life of Hashem and by your own life, I am not going to abandon you,” he is stating that Hashem is alive, and that the party to whom he makes such a statement is alive. Using the name of the Lord as relevant to one’s own standing, is something which makes it such a severe sin if it turns out that one does not honour such a vow or oath.
(1) איש כי ידור נדר, When a man vows a vow, etc. Why did the Torah repeat both the word נדר, vow, and the word שבעה, oath? Why could the Torah not simply have written איש כי ידור לה׳ או ישבע? Furthermore, why did the Torah phrase observance both in a positive and in a negative connotation, i.e. "he must not profane his word, as well as he must do in accordance with what came out of his mouth?" I believe we must look for the key to the way the Torah worded this legislation by remembering that there are two categories of vows and oaths. One category is related to a person's soul, i.e. he may undertake to study Torah, give a certain amount of charity, refrain from abominable practices, not to visit places predominantly visited by women, etc. The other category of vows and oaths pertains to the body and involves matters which are neither forbidden to us nor are we commanded to do them. Here too there are two divisions; one may vow to eat certain things, drink certain liquids, or live in a certain house, etc. Or, one may undertake on oath not to eat certain things, drink certain liquids, or wear certain clothes. G'd legislated here how a person should best conduct himself. The words כי ידור נדר, i.e. an ordinary vow involves an undertaking to go to a certain place or to perform a certain task. The addition of the word לה׳ means that different rules apply when the vow is not of a secular nature but relates to one's conduct vis-a-vis G'd. The addition of this word therefore means that the word נדר has not been repeated at all, but that once it applies to secular vows and once to religious vows. (2) The Torah goes on או השבע שבעה, "or he swears an oath, etc." In the first instance the oath concerns something one undertakes not to do as stated here לאסור אסר על נפשו, "to deny himself something." Here too we have two categories of oaths. One may swear not to do something which is already forbidden, as Boaz did when he wanted to reinforce his resolution not to sin by swearing an oath.
(יד) כׇּל־נֵ֛דֶר וְכׇל־שְׁבֻעַ֥ת אִסָּ֖ר לְעַנֹּ֣ת נָ֑פֶשׁ אִישָׁ֥הּ יְקִימֶ֖נּוּ וְאִישָׁ֥הּ יְפֵרֶֽנּוּ׃ (טו) וְאִם־הַחֲרֵשׁ֩ יַחֲרִ֨ישׁ לָ֥הּ אִישָׁהּ֮ מִיּ֣וֹם אֶל־יוֹם֒ וְהֵקִים֙ אֶת־כׇּל־נְדָרֶ֔יהָ א֥וֹ אֶת־כׇּל־אֱסָרֶ֖יהָ אֲשֶׁ֣ר עָלֶ֑יהָ הֵקִ֣ים אֹתָ֔ם כִּי־הֶחֱרִ֥שׁ לָ֖הּ בְּי֥וֹם שׇׁמְעֽוֹ׃ (טז) וְאִם־הָפֵ֥ר יָפֵ֛ר אֹתָ֖ם אַחֲרֵ֣י שׇׁמְע֑וֹ וְנָשָׂ֖א אֶת־עֲוֺנָֽהּ׃
(14) Every vow and every sworn obligation of self-denial may be upheld by her husband or annulled by her husband. (15) If her husband offers no objection from that day to the next, he has upheld all the vows or obligations she has assumed: he has upheld them by offering no objection on the day he found out. (16) But if he annuls them after [the day] he finds out, he shall bear her guilt.
כל נדר וכל שבועת אסר לענות נפש. למדך הכתוב כי מה שנתנה תורה רשות לבעל להפר נדרי אשתו אין זה בכל הנדרים שבעולם אלא דברים שיש בהן ענוי נפש, כגון שלא תרחץ ושלא תתקשט בבגדי צבעונין ושלא תאכל בשר ושלא תשתה יין ושלא תכחול ושלא תפרכס, וכיוצא בהן, ואפילו אסרה על עצמה פירות חנוני פלוני, יפר, וכל שכן שמפר דברים שבינו לבינה בעניני צניעות, ממה שכתוב בין איש לאשתו, ובשני ענינים אלו הוא שיש לבעל כח להפר לפי שהיא משועבדת לו בשני דברים, של ענוי נפש שיראה אותה יפה ושלא תתענה ולא תצטער, וכמו שאמרו ז"ל כי היא היתה אם כל חי, לחיים נתנה ולא לצער, דברים שבינו לבינה אין צריך לומר שהיא משועבדת לו בהן, ובודאי כל הנודרת באותן שני ענינים על דעת בעלה היא נודרת כיון שמשועבדת לו בהן, אבל דברים אחרים חוץ מהן שנדרה בהן האשה אין לבעל כח להפר אלא צריכה היתר חכם ע"י חרטה כשאר בני אדם.
כל נדר וכל שבועת אסר לענות נפש, “any vow or oath which results in a personal affliction, etc.” Here the Torah teaches that the fact that the Torah has granted the husband of a woman the right to interfere with her vows and to annul them is not a carte blanche applicable to any type of vow. The husband’s authority applies only when such a vow results in personal pain or discomfort also involving him in his marital status. If his wife were to vow not to wash or bathe herself, keeping such a vow would clearly interfere with their marital life; as a result of such considerations the Torah permitted her husband a veto power over such vows. It goes without saying that the husband can veto any vow of his wife which would interfere directly with their family life together. The husband’s authority extends to his wife’s vowing not to use eye-shadow or even certain products for sale in specific stores. We derive all this from the words בין איש לאשתו “between man and his wife,” in verse 17. The reason the husband has the right to interfere in vows concerning either ענוי נפש, self-affliction, and matters directly involving inter-marital relations is that his wife (any wife) is subservient to her husband in two areas; he is entitled to demand that his wife appear attractive to him and not take measures which result in her becoming physically repugnant to her husband. Our sages in Ketuvot 62 understood this concept as derived form Genesis 3,20 “for she (Chavah) is the mother of all living beings,” as meaning that the wife’s purpose in life is to enhance the quality of life of her husband not the reverse.
