Mishnayos Yevamos Perek 3 Mishnah 6

In the case of three brothers, two of whom were married to two sisters and one who was married to an unrelated woman, the following occurred: The husband of one of the sisters died childless, and the brother who was married to the unrelated woman married, i.e., performed lev irate marriage with, the deceased brother’s wife and later died himself, childless. In this situation, both women happen for levirate marriage before the other, remaining, brother. The first woman is dismissed due to the prohibition proscribing the sister of one’s wife, as she is the sister of this brother’s wife, and the second woman is dismissed due to her status as the first woman’s rival wife. Following the first levirate marriage, this second woman became the rival wife of the sister, and is therefore exempt from levirate marriage as well. If, however, the brother married to the unrelated woman performed only levirate betrothal, but had not yet consummated the levirate marriage with the sister, and he died, the unrelated woman, whose halakhic status with regard to yibbum is similar to that of a sister’s rival wife, must perform ḥalitza and may not enter into levirate marriage. In the case of three brothers, two of whom were married to two sisters and one who was married to an unrelated woman, the following occurred: One of the husbands of the sisters died, and he who was married to the unrelated woman married the deceased husband’s wife, and then the wife of the second brother, the other one of the sisters, died. Afterward, the brother who was married to the unrelated woman died, leaving two women for levirate marriage before the remaining brother: The unrelated woman and the woman who was previously prohibited as the sister of his deceased wife. In this case, the sister is forbidden to him forever. She is not forbidden due to her status as his wife’s sister, as his wife already died and one’s wife’s sister is permitted after the wife’s death. However, since she was already forbidden to him at one time, she is forbidden to him forever. When she first happened before the brothers for levirate marriage, before the third brother married her, she was forbidden to the second brother as his wife’s sister. Therefore, she is forbidden to him forever. In addition, she exempts her rival wife, the unrelated woman, from levirate marriage.

שְׁלֹשָׁה אַחִין, שְׁנַיִם מֵהֶן נְשׂוּאִים שְׁתֵּי אֲחָיוֹת, וְאֶחָד נָשׂוּי נָכְרִית, מֵת אֶחָד מִבַּעֲלֵי אֲחָיוֹת, וְכָנַס נָשׂוּי נָכְרִית אֶת אִשְׁתּוֹ, וָמֵת, הָרִאשׁוֹנָה יוֹצְאָה מִשּׁוּם אֲחוֹת אִשָּׁה, וּשְׁנִיָּה מִשּׁוּם צָרָתָהּ. עָשָׂה בָהּ מַאֲמָר, וָמֵת, נָכְרִית חוֹלֶצֶת וְלֹא מִתְיַבֶּמֶת. שְׁלֹשָׁה אַחִים, שְׁנַיִם מֵהֶם נְשׂוּאִים שְׁתֵּי אֲחָיוֹת, וְאֶחָד נָשׂוּי נָכְרִית, מֵת הַנָּשׂוּי נָכְרִית, וְכָנַס אֶחָד מִבַּעֲלֵי אֲחָיוֹת אֶת אִשְׁתּוֹ, וָמֵת, הָרִאשׁוֹנָה יוֹצְאָה מִשּׁוּם אֲחוֹת אִשָּׁה, וּשְׁנִיָּה מִשּׁוּם צָרָתָהּ. עָשָׂה בָהּ מַאֲמָר, וָמֵת, נָכְרִית חוֹלֶצֶת וְלֹא מִתְיַבֶּמֶת: