Mishnayos Yevamos Perek 3 Mishnah 5

In the case of three brothers, two of whom were married to two sisters, and one who was single, the following occurred: The husband of one of the sisters died childless, leaving behind his wife, and the single brother performed levirate betrothal [ma’amar] to this wife. The single brother performed an act of betrothal to the yevama but did not yet consummate the marriage by engaging in sexual intercourse. Afterward, the second brother died, and therefore the second brother’s wife, the sister of the betrothed, happened before the single brother for levirate marriage as well. In this case, Beit Shammai say: His wife remains with him. The woman he betrothed is considered like his wife, and he is not required to divorce her. And this other woman leaves the yavam and is exempt from levirate marriage as the sister of a wife. Beit Hillel say: Being as he had not yet entered into marriage with the first woman, he is required to perform levirate marriage with both women. Therefore, he divorces his wife, i.e., the woman to whom he performed levirate betrothal, with a bill of divorce, which nullifies levirate betrothal, and by ḥalitza, which nullifies the levirate bond. And, he sends away the wife of his second brother with ḥalitza as well. They comment: This is the case that was referred to when the Sages said: Woe unto him for his wife and woe unto him for the wife of his brother. Due to the combination of circumstances, he loses them both.

שְׁלֹשָׁה אַחִין, שְׁנַיִם מֵהֶם נְשׂוּאִים שְׁתֵּי אֲחָיוֹת, וְאֶחָד מֻפְנֶה, מֵת אֶחָד מִבַּעֲלֵי אֲחָיוֹת, וְעָשָׂה בָהּ מֻפְנֶה מַאֲמָר, וְאַחַר כָּךְ מֵת אָחִיו הַשֵּׁנִי, בֵּית שַׁמַּאי אוֹמְרִים, אִשְׁתּוֹ עִמּוֹ, וְהַלָּה תֵצֵא מִשּׁוּם אֲחוֹת אִשָּׁה. וּבֵית הִלֵּל אוֹמְרִים, מוֹצִיא אֶת אִשְׁתּוֹ בְגֵט וּבַחֲלִיצָה, וְאֵשֶׁת אָחִיו בַּחֲלִיצָה. זוֹ הִיא שֶׁאָמְרוּ, אוֹי לוֹ עַל אִשְׁתּוֹ וְאוֹי לוֹ עַל אֵשֶׁת אָחִיו: