Mishnah Yevamot
1א׳
1 א

חֲמֵשׁ עֶשְׂרֵה נָשִׁים פּוֹטְרוֹת צָרוֹתֵיהֶן וְצָרוֹת צָרוֹתֵיהֶן מִן הַחֲלִיצָה וּמִן הַיִּבּוּם עַד סוֹף הָעוֹלָם. וְאֵלּוּ הֵן, בִּתּוֹ, וּבַת בִּתּוֹ, וּבַת בְּנוֹ, בַּת אִשְׁתּוֹ, וּבַת בְּנָהּ, וּבַת בִּתָּהּ, חֲמוֹתוֹ וְאֵם חֲמוֹתוֹ, וְאֵם חָמִיו, אֲחוֹתוֹ מֵאִמּוֹ, וַאֲחוֹת אִמּוֹ, וַאֲחוֹת אִשְׁתּוֹ, וְאֵשֶׁת אָחִיו מֵאִמּוֹ, וְאֵשֶׁת אָחִיו שֶׁלֹּא הָיָה בְעוֹלָמוֹ, וְכַלָּתוֹ, הֲרֵי אֵלּוּ פּוֹטְרוֹת צָרוֹתֵיהֶן וְצָרוֹת צָרוֹתֵיהֶן מִן הַחֲלִיצָה וּמִן הַיִּבּוּם עַד סוֹף הָעוֹלָם. וְכֻלָּן אִם מֵתוּ, אוֹ מֵאֲנוּ, אוֹ נִתְגָּרְשׁוּ, אוֹ שֶׁנִּמְצְאוּ אַיְלוֹנִיּוֹת, צָרוֹתֵיהֶן מֻתָּרוֹת. וְאִי אַתָּה יָכוֹל לוֹמַר בַּחֲמוֹתוֹ וּבְאֵם חֲמוֹתוֹ וּבְאֵם חָמִיו שֶׁנִּמְצְאוּ אַיְלוֹנִיּוֹת אוֹ שֶּׁמֵּאֵנוּ:

Fifteen classes of women exempt their rivals and their rivals' rivals ad infinitum from Chalitzah [the ceremony releasing the widow of a childless man from the obligation of Levirate marriage] and Yibum [Levirate marriage wherein a man weds his childless brother's widow]. And these are they: His [the Yavam - the surviving brother's] daughter, and his daughter's daughter, and his son's daughter, and his wife's daughter, and her [his wife's] son's daughter, and her [his wife's] daughter's daughter, and his mother-in-law, and his mother-in-law's mother, and his father-in-law's mother, and his maternal sister, and his mother's sister, and his wife's sister, and his maternal brother's wife, and the wife of his brother who was not alive [when the younger brother lived], and his daughter-in-law. These exempt their rivals and their rivals' rivals from Chalitzah and from Yibum ad infinitum. [If] any of these [women] died, or refused [as adults to remain in marriages they were forced into as minors], or were divorced, or were found to be barren, their rivals are permitted [to the Yavam]. But regarding his mother-in-law, and his mother-in-law's mother, and his father-in-law's mother you cannot say that they were found to be barren or that they refused.

2 ב

כֵּיצַד פּוֹטְרוֹת צָרוֹתֵיהֶן. הָיְתָה בִּתּוֹ אוֹ אַחַת מִכָּל הָעֲרָיוֹת הָאֵלּוּ נְשׂוּאָה לְאָחִיו, וְלוֹ אִשָּׁה אַחֶרֶת, וָמֵת, כְּשֵׁם שֶׁבִּתּוֹ פְּטוּרָה, כָּךְ צָרָתָהּ פְּטוּרָה. הָלְכָה צָרַת בִּתּוֹ וְנִשֵּׂאת לְאָחִיו הַשֵּׁנִי, וְלוֹ אִשָּׁה אַחֶרֶת, וָמֵת, כְּשֵׁם שֶׁצָּרַת בִּתּוֹ פְּטוּרָה, כָּךְ צָרַת צָרָתָהּ פְּטוּרָה, אֲפִלּוּ הֵן מֵאָה. כֵּיצַד אִם מֵתוּ צָרוֹתֵיהֶן מֻתָּרוֹת, הָיְתָה בִתּוֹ אוֹ אַחַת מִכָּל הָעֲרָיוֹת הָאֵלּוּ נְשׂוּאָה לְאָחִיו, וְלוֹ אִשָּׁה אַחֶרֶת, מֵתָה בִתּוֹ אוֹ נִתְגָּרְשָׁה, וְאַחַר כָּךְ מֵת אָחִיו, צָרָתָהּ מֻתֶּרֶת. וְכָל הַיְכוֹלָה לְמָאֵן וְלֹא מֵאֲנָה, צָרָתָהּ חוֹלֶצֶת וְלֹא מִתְיַבֶּמֶת:

How do they [these women] exempt their rivals? [If] one's daughter or any one of these forbidden unions was married to his brother who had another wife, and he died - then just like his daughter is exempt [from Yibum because one cannot marry one's daughter], so too is her rival exempt. [If] his daughter's rival went and married his second brother who had another wife and then he [the second brother] died - then just like his daughter's rival is exempt [from Yibum] so too is her rival's rival exempt, even if there are a hundred [brothers]. How is it to be understood that when these have died their rivals are permitted? [If] one's daughter, or any one of these forbidden unions was married to his brother who had another wife, and his daughter died, or was divorced, and subsequently his brother died, her rival is permitted. And [if] a woman could have refused but did not refuse, her rival performs Chalitzah but does not undergo Yibum.

3 ג

שֵׁשׁ עֲרָיוֹת חֲמוּרוֹת מֵאֵלּוּ, מִפְּנֵי שֶׁנְּשׂוּאוֹת לַאֲחֵרִים, צָרוֹתֵיהֶן מֻתָּרוֹת. אִמּוֹ, וְאֵשֶׁת אָבִיו, וַאֲחוֹת אָבִיו, אֲחוֹתוֹ מֵאָבִיו, וְאֵשֶׁת אֲחִי אָבִיו, וְאֵשֶׁת אָחִיו מֵאָבִיו:

[There are] six forbidden unions [whose cases are] more stringent than these, because they are married to others their rivals are permitted. His mother, and his father's wife, and his father's sister, and his paternal sister, and his father's brother's wife, and his paternal brother's wife.

4 ד

בֵּית שַׁמַּאי מַתִּירִין הַצָּרוֹת לָאַחִים, וּבֵית הִלֵּל אוֹסְרִים. חָלְצוּ, בֵּית שַׁמַּאי פּוֹסְלִין מִן הַכְּהֻנָּה, וּבֵית הִלֵּל מַכְשִׁירִים. נִתְיַבְּמוּ, בֵּית שַׁמַּאי מַכְשִׁירִים, וּבֵית הִלֵּל פּוֹסְלִין. אַף עַל פִּי שֶׁאֵלּוּ אוֹסְרִין וְאֵלּוּ מַתִּירִין, אֵלּוּ פּוֹסְלִין וְאֵלּוּ מַכְשִׁירִין, לֹא נִמְנְעוּ בֵּית שַׁמַּאי מִלִּשָּׂא נָשִׁים מִבֵּית הִלֵּל, וְלֹא בֵית הִלֵּל מִבֵּית שַׁמַּאי. כָּל הַטָּהֳרוֹת וְהַטֻּמְאוֹת שֶׁהָיוּ אֵלּוּ מְטַהֲרִין וְאֵלּוּ מְטַמְּאִין, לֹא נִמְנְעוּ עוֹשִׂין טָהֳרוֹת אֵלּוּ עַל גַּבֵּי אֵלּוּ:

Beit Shammai permit the rivals to the brothers [for marriage], but Beit Hillel forbid [them]. [If these women] had performed Chalitzah Beit Shammai disqualify them from [subsequently marrying] priests, but Beit Hillel allow them [to do so]. [If these women] had undergone Yibum, Beit Shammai permit them [to subsequently marry priests], but Beit Hillel disqualify them [from such a union]. Even though these [one school] prohibit and these [the other school] permit, these disqualify and these allow, Beit Shammai did not refrain from marrying women from Beit Hillel, nor did Beit Hillel [refrain from marrying women] from Beit Shammai. [With regard to] purity and impurity where these ruled [a matter] pure and these ruled [it] impure, they did not refrain from using [utensils] the other deemed pure.