יבמות צה

יבמות צה

אֲחוֹת אִשָּׁה, דִּבְמֵזִיד לָא אֲסִירָא מִדְּאוֹרָיְיתָא, בְּשׁוֹגֵג לָא גְּזַרוּ בַּהּ רַבָּנַן. וּמְנָלַן דְּלָא אֲסִירָא, דְּתַנְיָא: ״אוֹתָהּ״, אוֹתָהּ — שְׁכִיבָתָהּ אוֹסַרְתָּהּ, וְאֵין שְׁכִיבַת אֲחוֹתָהּ אוֹסַרְתָּהּ.

However, with regard to a wife’s sister, where even if the sister sins intentionally the wife is not forbidden to him by Torah law, if he did so unwittingly the Sages did not decree with regard to him. And from where do we derive that she is not forbidden? As it is taught in a baraita that in the verse: “A man, when his wife goes aside…and a man lies with her” (Numbers 5:12–13), the emphasis of “her” teaches: It is her intercourse with another man that renders her forbidden to her husband, but the intercourse of her sister does not render her forbidden.

שֶׁיָּכוֹל, וַהֲלֹא דִּין הוּא: וּמָה בִּמְקוֹם שֶׁבָּא עַל אִיסּוּר קַל — נֶאֱסָר הָאוֹסֵר, מְקוֹם שֶׁבָּא עַל אִיסּוּר חָמוּר — אֵינוֹ דִּין שֶׁנֶּאֱסָר הָאוֹסֵר.

As, were it not for this verse, one might have thought: Could this not be derived through an a fortiori inference: And if in a case where he has relations subject to a light prohibition, the one causing her to be rendered prohibited is forbidden, then in a situation where he has intercourse subject to a severe prohibition, is it not right that the one causing her to be rendered prohibited should be forbidden? This a fortiori inference will be explained later in the Gemara.

אָמַר רַבִּי יְהוּדָה: לֹא נֶחְלְקוּ בֵּית שַׁמַּאי וּבֵית הִלֵּל בְּבָא עַל חֲמוֹתוֹ שֶׁפָּסַל אֶת אִשְׁתּוֹ, עַל מָה נֶחְלְקוּ — בְּבָא עַל אֲחוֹת אִשְׁתּוֹ, שֶׁבֵּית שַׁמַּאי אוֹמְרִים: פָּסַל, וּבֵית הִלֵּל אוֹמְרִים: לֹא פָּסַל. אָמַר רַבִּי יוֹסֵי: לֹא נֶחְלְקוּ בֵּית שַׁמַּאי וּבֵית הִלֵּל בְּבָא עַל אֲחוֹת אִשְׁתּוֹ שֶׁלֹּא פָּסַל אֶת אִשְׁתּוֹ, עַל מָה נֶחְלְקוּ — בְּבָא עַל חֲמוֹתוֹ, שֶׁבֵּית שַׁמַּאי אוֹמְרִים: פָּסַל, וּבֵית הִלֵּל אוֹמְרִים: לֹא פָּסַל.

Rabbi Yehuda said: Beit Shammai and Beit Hillel did not disagree with regard to one who has relations with his mother-in-law, that he renders his wife disqualified from remaining married to him. With regard to what case did they disagree? With regard to one who has relations with his wife’s sister, as Beit Shammai say that he renders his wife disqualified, and Beit Hillel say he does not render her disqualified. Rabbi Yosei said: Not so, as Beit Shammai and Beit Hillel did not disagree with regard to one who has relations with his wife’s sister, that he does not render his wife disqualified from remaining married to him. With regard to what did they disagree? With regard to one who has relations with his mother-in-law, as Beit Shammai say he renders his wife disqualified and Beit Hillel say he does not render her disqualified.

לְפִי שֶׁבַּתְּחִלָּה, הוּא מוּתָּר בְּכׇל הַנָּשִׁים שֶׁבָּעוֹלָם, וְהִיא מוּתֶּרֶת בְּכׇל הָאֲנָשִׁים שֶׁבָּעוֹלָם. קִדְּשָׁהּ — הוּא אֲסָרָהּ, וְהִיא אֲסָרַתּוּ. מְרוּבֶּה אִיסּוּר שֶׁאֲסָרָהּ, מֵאִיסּוּר שֶׁאֲסָרַתְהוּ. שֶׁהוּא אֲסָרָהּ בְּכׇל אֲנָשִׁים שֶׁבָּעוֹלָם, וְהִיא לָא אֲסָרַתְהוּ אֶלָּא בִּקְרוֹבוֹתֶיהָ.

Rabbi Yosei explains why Beit Shammai and Beit Hillel did not disagree with regard to the case of one who has relations with his wife’s sister. This is because at first, before the marriage, he is permitted to all the women in the world and she is permitted to all the men in the world. After he has betrothed her as his wife, he renders her forbidden to all men, and she renders him forbidden to her relatives. Consequently, the prohibition by which he renders her forbidden is greater than the prohibition by which she renders him forbidden, as he renders her forbidden to all the men in the world and she renders him forbidden by their betrothal only to her relatives.

וַהֲלֹא דִּין הוּא: וּמָה הוּא, שֶׁאֲסָרָהּ בְּכׇל אֲנָשִׁים שֶׁבָּעוֹלָם, שָׁגְגָה בָּאָסוּר לָהּ — אֵינָהּ נֶאֱסֶרֶת בַּמּוּתָּר לָהּ, הִיא, שֶׁלֹּא אֲסָרַתְהוּ אֶלָּא בִּקְרוֹבוֹתֶיהָ, שָׁגַג בָּאָסוּר לוֹ — אֵינוֹ דִּין שֶׁלֹּא נֶאֱסַר (לוֹ) בַּמּוּתָּר לוֹ?!

Rabbi Yosei’s explanation continues. Could this halakha of a wife’s sister not be derived through an a fortiori inference: And if he prohibited her through their betrothal to all men in the world, and yet she was unwitting with one forbidden to her, i.e., she had relations with another man by mistake, she is not forbidden to he who is permitted to her, her husband; she, who prohibited him only to her relatives, if he was unwitting with one forbidden to him, her sister, is it not right that we should not render him forbidden to her, she who is permitted to him, namely his wife?

וְזֶה הַדִּין לְשׁוֹגֵג. לְמֵזִיד מִנַּיִן? תַּלְמוּד לוֹמַר: ״אוֹתָהּ״, אוֹתָהּ — שְׁכִיבָתָהּ אוֹסַרְתָּהּ, וְאֵין שְׁכִיבַת אֲחוֹתָהּ אוֹסַרְתָּהּ.

And this is the a fortiori inference and the reason for the halakha of an unwitting sinner, i.e., that if he had unwitting relations with one of his wife’s relations the wife is not thereby rendered forbidden to him. With regard to one whose act was intentional, from where is the halakha derived? The verse states: “Her,” meaning that it is her intercourse with another man that renders her forbidden to her husband, but the intercourse of her husband with her sister does not render her forbidden to him.

אָמַר רַבִּי אַמֵּי אָמַר רֵישׁ לָקִישׁ: מַאי טַעְמָא דְּרַבִּי יְהוּדָה — דִּכְתִיב: ״בָּאֵשׁ יִשְׂרְפוּ אוֹתוֹ וְאֶתְהֶן״, וְכִי כׇּל הַבַּיִת כּוּלּוֹ בִּשְׂרֵפָה?! אִם אֵינוֹ עִנְיָן לִשְׂרֵפָה, תְּנֵהוּ עִנְיָן לְאִיסּוּרָא.

Rabbi Ami said that Reish Lakish said: What is the reason of Rabbi Yehuda, who maintains that one who has intercourse with his mother-in-law is forbidden to his wife? As it is written: “They shall be burned in fire, he and they” (Leviticus 20:14). This verse is puzzling: And shall the entire house be punished by burning? Why should both women be punished when only one of them transgressed? If it does not refer to the matter of burning, refer it to the matter of a prohibition, that they are both forbidden to him. This teaches that he is forbidden not only to the woman with whom he sinned, but also to his wife.

אָמַר רַב יְהוּדָה אָמַר שְׁמוּאֵל: אֵין הֲלָכָה כְּרַבִּי יְהוּדָה. הָהוּא דַּעֲבַד אִיסּוּרָא בַּחֲמָתֵיהּ. אַתְיֵיהּ רַב יְהוּדָה, נַגְּדֵיהּ. אֲמַר לֵיהּ: אִי לָאו דְּאָמַר שְׁמוּאֵל אֵין הֲלָכָה כְּרַבִּי יְהוּדָה — אַסְרִיתַהּ עֲלָךְ אִיסּוּרָא דְעָלַם.

Rav Yehuda said that Shmuel said: The halakha is not in accordance with the opinion of Rabbi Yehuda. The Gemara relates: A certain individual performed a transgression by having relations with his mother-in-law. Rav Yehuda had him brought for judgment and ordered that he be flogged. He said to him: If it were not for the fact that Shmuel said the halakha is not in accordance with the opinion of Rabbi Yehuda, I would render your wife forbidden to you permanently.

מַאי ״אִיסּוּר קַל״? אָמַר רַב חִסְדָּא: מַחְזִיר גְּרוּשָׁתוֹ מִשֶּׁנִּשֵּׂאת.

§ At the start of the baraita the tanna stated an a fortiori inference that is not entirely clear: If in a place where he has relations subject to a light prohibition, the one causing her to be rendered prohibited is forbidden. The Gemara asks: What is this light prohibition? Rav Ḥisda said: It is referring to one who remarries his divorcée after she married another man.

בָּא עָלֶיהָ הַאי — אַסְרַהּ עֲלֵיהּ דְּהַאי. בָּא עָלֶיהָ אִידַּךְ — אַסְרַהּ עֲלֵיהּ דְּהַאי.

The Gemara explains that according to this interpretation the a fortiori inference should be understood as follows: If this one, the second husband, has relations with her, he has rendered her forbidden to that one, the first husband. And if the second man divorced her and then the other one, the first husband, had relations with her, he has likewise rendered her forbidden to this one. This demonstrates that even with regard to a light prohibition the man who renders her forbidden is also forbidden by this intercourse.

מָה לְמַחְזִיר גְּרוּשָׁתוֹ מִשֶּׁנִּשֵּׂאת, שֶׁכֵּן נִטְמָא הַגּוּף, וְאִיסּוּרָהּ בְּרוֹב, וְאִיסּוּרָהּ אִיסּוּר עוֹלָם.

The Gemara refutes this interpretation: What about the fact that one who remarries his divorcée after she married another man cannot be considered to have violated a light prohibition, as the prohibition is stringent in several regards: As the body is defiled by this intercourse, for the Torah states “after she has been defiled” (Deuteronomy 24:4); and her prohibition applies to the majority of the Jewish people, not to select groups; and her prohibition is an irrevocable prohibition, as she is no longer permitted to her first husband after having relations with her second husband. This last stringency is not true of his wife’s sister, who is permitted to him after the death of his wife.

אֶלָּא אָמַר רֵישׁ לָקִישׁ: יְבָמָה. יְבָמָה לְמַאן? אִילֵּימָא לְאַחֵר, וְכִדְרַב הַמְנוּנָא, דְּאָמַר רַב הַמְנוּנָא: שׁוֹמֶרֶת יָבָם שֶׁזִּינְּתָה אֲסוּרָה לִיבָמָהּ —

Rather, the Gemara rejects this explanation in favor of the following one that Reish Lakish said: The baraita is referring to relations with a yevama, which is called a light prohibition, as the man who has relations with her is forbidden to her. The Gemara clarifies: With regard to this yevama, with whom did she engage in intercourse? If we say that she had relations with another man, not her yavam, this would mean that the ruling is in accordance with the opinion of Rav Hamnuna. As Rav Hamnuna said: A widow waiting for her yavam who engaged in licentious sexual relations with another man is forbidden to her yavam. The argument would be as follows: Although the yavam renders the yevama forbidden to every other man, if she has relations with another she becomes forbidden to him as well.

מָה לִיבָמָה שֶׁכֵּן נִטְמָא הַגּוּף, וְאִיסּוּרָהּ בְּרוֹב.

However, this argument can also be challenged: What about the fact that in the case of a yevama who engages in this forbidden relationship, the body is defiled and her prohibition applies equally to the majority of the people. Therefore, one cannot derive the prohibitions of one’s wife’s relatives from this halakha.

אֶלָּא יְבָמָה לָאַחִין. עֲבַד בַּהּ מַאֲמָר הַאי — אַסְרַהּ עֲלֵיהּ דְּהַאי. בָּא עָלֶיהָ אִידַּךְ — אַסְרַהּ עֲלֵיהּ דְּהַאי. מַאי אִירְיָא שֶׁבָּא עָלֶיהָ שֵׁנִי? אֲפִילּוּ עֲבַד בָּהּ נָמֵי מַאֲמָר!

Rather, the baraita must be referring to a case of a yevama to the brothers, as follows: If this brother performed levirate betrothal [ma’amar] with her he has rendered her forbidden to that one, the other brothers, as she is effectively betrothed to him. If one of the other brothers, who had not performed levirate betrothal with her, subsequently has relations with her, he has rendered her forbidden to this one who had performed levirate betrothal with her. The Gemara asks: If that is the meaning of the baraita, why specifically state that the second had relations with her? Even if he performed levirate betrothal with her too, he thereby renders her forbidden to the first brother, which proves that it is not the act of intercourse itself that causes the prohibition.

הָא לָא קַשְׁיָא, כְּרַבָּן גַּמְלִיאֵל, דְּאָמַר: אֵין מַאֲמָר אַחַר מַאֲמָר. אֶלָּא, אֲפִילּוּ נָתַן לָהּ גֵּט, וַאֲפִילּוּ חָלַץ לָהּ!

The Gemara refutes this suggestion: This is not difficult, as it can be explained in accordance with the opinion of Rabban Gamliel, who said: There is no levirate betrothal after a levirate betrothal, i.e., if one brother performed levirate betrothal with the yevama, no other levirate betrothal is of any effect. However, this explanation can still be refuted, as her prohibition to the yavam is not due to the act of intercourse, as even if the other brother gave her a bill of divorce, or even if he performed ḥalitza with her, he has likewise rendered her forbidden to the first brother, who performed levirate betrothal.

אֶלָּא אָמַר רַבִּי יוֹחָנָן: סוֹטָה. סוֹטָה לְמַאן? אִילֵימָא לַבַּעַל: בָּא עָלֶיהָ בַּעַל — אַסְרַהּ עֲלֵיהּ דְּבוֹעֵל. מַאי אִירְיָא בָּא עָלֶיהָ? אֲפִילּוּ נָתַן לָהּ גֵּט — וַאֲפִילּוּ אָמַר ״אֵין אֲנִי מַשְׁקֶה״!

Rather, Rabbi Yoḥanan said: The light prohibition is that of a sota. The Gemara asks: This sota, to whom is she forbidden? If we say that she is forbidden to the husband, the explanation would be as follows: If her husband has relations with her, despite the fact that she is forbidden to him after she disobeyed his warning not to seclude herself with a certain man, he has rendered her forbidden to the fornicator, as she is barred from marrying him even if her husband divorces her. However, why is this true specifically in a case in which he had relations with her? Even if her husband only gave her a bill of divorce and did not have relations with her after her seclusion, or even if he said: I will not force her to drink the waters of a sota, she is likewise forbidden to the other man.

אֶלָּא סוֹטָה לַבּוֹעֵל. הַאי אִיסּוּר קַל הוּא? אִיסּוּר חָמוּר הוּא, דְּהַיְינוּ אֵשֶׁת אִישׁ!

Rather, the baraita is referring to a sota who had relations with the fornicator, thereby rendering herself permanently forbidden to her husband, as she was a married woman at the time. Yet this too is puzzling: Is this a light prohibition? It is a severe prohibition, as this is the prohibition proscribing a married woman, one of the most serious of all prohibitions.

אֶלָּא אָמַר רָבָא: אֵשֶׁת אִישׁ. וְכֵן כִּי אֲתָא רָבִין, אָמַר רַבִּי יוֹחָנָן: אֵשֶׁת אִישׁ. וּמַאי קָרֵי לַהּ ״אִיסּוּר קַל״ — שֶׁאֵין הָאוֹסְרָהּ אוֹסְרָהּ כׇּל יָמָיו. תַּנְיָא נָמֵי הָכִי: אַבָּא חָנָן אָמַר מִשּׁוּם רַבִּי אֶלְעָזָר: אֵשֶׁת אִישׁ.

Rather, Rava said that the light prohibition is actually that of a married woman. And similarly, when Ravin came from Eretz Yisrael, he said that Rabbi Yoḥanan said that the baraita is referring to a married woman. And for what reason does the tanna call this a light prohibition? The reason is that it differs from and is more lenient than other prohibitions in that her husband, who renders her forbidden, does not render her forbidden for his whole lifetime, as he can negate the prohibition by giving her a bill of divorce. This is also taught in a baraita: Abba Ḥanan said in the name of Rabbi Elazar: The baraita is referring to a married woman.

וּמָה בִּמְקוֹם הַבָּא עַל אִיסּוּר קַל, שֶׁאֵין הָאוֹסְרָהּ אוֹסְרָהּ כׇּל יָמָיו — נֶאֱסָר הָאוֹסֵר, הַבָּא עַל אִיסּוּר חָמוּר, שֶׁהָאוֹסְרָהּ אוֹסְרָהּ כׇּל יָמָיו — אֵינוֹ דִּין שֶׁנֶּאֱסָר הָאוֹסְרָהּ?

The Gemara explains that according to this opinion the a fortiori inference should be understood as follows: And if in a case where he has relations with a married woman, which is a light prohibition, due to the fact that he who renders her forbidden does not render her forbidden for his whole lifetime, and yet the one who renders her forbidden is forbidden, as the husband of a woman who committed adultery is permanently barred from having relations with her, then the following conclusion is correct: One who has relations subject to a severe transgression, e.g., a wife’s sister, which is severe because the one who renders his wife forbidden renders her forbidden for her whole lifetime, since as long as his wife remains alive he is forbidden to her sister, is it not right that the one who renders her forbidden should be forbidden?

תַּלְמוּד לוֹמַר: ״אוֹתָהּ״, אוֹתָהּ — שְׁכִיבָתָהּ אוֹסַרְתָּהּ, וְאֵין שְׁכִיבַת אֲחוֹתָהּ אוֹסַרְתָּהּ.

The verse therefore states: “Her,” from which it is derived: It is her intercourse that renders her forbidden, but the intercourse of her sister does not render her forbidden.

רַבִּי יוֹסֵי אוֹמֵר: כֹּל שֶׁפּוֹסֵל וְכוּ׳. מַאי קָאָמַר רַבִּי יוֹסֵי? אִילֵּימָא דְּקָאָמַר תַּנָּא קַמָּא, דְּאָזֵיל אִשְׁתּוֹ וְגִיסוֹ לִמְדִינַת הַיָּם — אֵשֶׁת גִּיסוֹ אֲסִירָא, וְאִשְׁתּוֹ שַׁרְיָא,

§ The mishna taught: Rabbi Yosei says: Whoever disqualifies others also disqualifies himself, and whoever does not disqualify others does not disqualify himself. The Gemara asks: What is it Rabbi Yosei is saying? If we say that the first tanna said that one’s wife and brother-in-law went overseas and he mistakenly had relations with his wife’s sister, who is married to his brother-in-law, and consequently the wife of his brother-in-law is forbidden to the brother-in-law, and his wife is permitted to him, this is problematic.

וְקָאָמַר לֵיהּ רַבִּי יוֹסֵי: כִּי הֵיכִי דְּאִשְׁתּוֹ שַׁרְיָא — אֵשֶׁת גִּיסוֹ נָמֵי שַׁרְיָא. אִי הָכִי, כׇּל שֶׁאֵין פּוֹסֵל עַל יְדֵי אֲחֵרִים — אֵין פּוֹסֵל עַל יְדֵי עַצְמוֹ, כֹּל שֶׁאֵין פּוֹסֵל עַל יְדֵי עַצְמוֹ — אֵינוֹ פּוֹסֵל עַל יְדֵי אֲחֵרִים, מִיבַּעְיָא לֵיהּ!

The Gemara elaborates: And according to this explanation, Rabbi Yosei says to the first tanna: Just as his wife is permitted to him, the wife of his brother-in-law is also permitted to her husband. Rabbi Yosei’s reasoning is that if he has not disqualified his wife to himself, due to the accidental nature of his relations with her sister, he should not disqualify the sister to her husband either. The Gemara continues: If so, the formulation of Rabbi Yosei’s statement is imprecise, as instead of saying: Whoever does not disqualify others does not disqualify himself, he should have said: Whoever does not disqualify himself, i.e., his sexual relations do not render his wife forbidden to him, does not disqualify others, i.e., the wife of the other man.

וְאֶלָּא כִּי הֵיכִי דְּאֵשֶׁת גִּיסוֹ אֲסִירָא — אִשְׁתּוֹ נָמֵי אֲסִירָא. הָתִינַח ״כֹּל שֶׁפּוֹסֵל״, — ״כֹּל שֶׁאֵינוֹ פּוֹסֵל״ מַאי עֲבִידְתֵּיהּ?

But rather, one might explain Rabbi Yosei’s teaching in the reverse manner: Just as the wife of his brother-in-law is forbidden to her husband, his own wife is also forbidden to him. This works out well with regard to the clause that starts with: Whoever disqualifies, as he disqualifies others, i.e., his brother-in-law’s wife to his brother-in-law, and therefore he also disqualifies his wife to himself. However, the continuation of the statement: Whoever does not disqualify, what is its purpose? This clause has no apparent relevance to Rabbi Yosei’s statement.

אָמַר רַבִּי אַמֵּי אַרֵישָׁא: נִיסֵּת עַל פִּי בֵּית דִּין — תֵּצֵא, וּפְטוּרָה מִן הַקׇּרְבָּן. עַל פִּי עֵדִים — תֵּצֵא, וְחַיֶּיבֶת בְּקׇרְבָּן. יִפָּה כֹּחוֹ שֶׁל בֵּית דִּין, שֶׁפֹּטְרָהּ מִן הַקׇּרְבָּן.

Rabbi Ami said: Rabbi Yosei’s statement does not refer to this halakha, but to the first mishna of the chapter, which taught that if a woman whose husband went overseas was informed that he was dead and she married by permission of the court she must leave her new husband and is exempt from bringing an offering. If she married based on the testimony of witnesses, without the authorization of the court, she must leave and is liable to bring an offering. In this regard, the power of the court is enhanced, as she is exempt from an offering.

וְקָאָמַר תַּנָּא קַמָּא: לָא שְׁנָא עַל פִּי עֵדִים, דְּאֵשֶׁת גִּיסוֹ שַׁרְיָא. וְלָא שְׁנָא עַל פִּי בֵּית דִּין, דְּאֵשֶׁת גִּיסוֹ אֲסִירָא.

Rabbi Ami explains: And accordingly, if his wife and brother-in-law went overseas and witnesses came and testified that they were both dead, the first tanna says that it is no different whether the wife of his brother-in-law married him based on the testimony of witnesses alone, in which case the wife of his brother-in-law is permitted to her husband, as she is considered as having acted under duress, having heard testimony that her husband was dead, and it is no different if she married him by permission of the court, as although the wife of his brother-in-law is prohibited, his own wife remains permitted to him.

וְקָאָמַר לֵיהּ רַבִּי יוֹסֵי: עַל פִּי בֵּית דִּין, דְּפוֹסֵל עַל יְדֵי אֲחֵרִים — פּוֹסֵל עַל יְדֵי עַצְמוֹ. עַל פִּי עֵדִים, דְּאֵינוֹ פּוֹסֵל עַל יְדֵי אֲחֵרִים — אֵינוֹ פּוֹסֵל עַל יְדֵי עַצְמוֹ.

Rabbi Ami continues his explanation. And Rabbi Yosei says to the first tanna: One who married by permission of the court, who disqualifies others, he also disqualified himself to his own wife; however, in the case of one who married based on the testimony of witnesses who does not disqualify others, I agree that he does not disqualify himself, and his wife is permitted to him.

רַבִּי יִצְחָק נַפָּחָא אָמַר: לְעוֹלָם אַסֵּיפָא (הָא — דִּנְסֵיב אֵשֶׁת גִּיסוֹ, וְהָא — דִּנְסֵיב אֲרוּסַת גִּיסוֹ). הָא — דְּאָזְלִי אֲרוּסָתוֹ וְגִיסוֹ, הָא — דְּאָזְלִי אִשְׁתּוֹ וְגִיסוֹ, וְקָאָמַר תַּנָּא קַמָּא: לָא שְׁנָא אִשְׁתּוֹ וְגִיסוֹ, וְלָא שְׁנָא אֲרוּסָתוֹ וְגִיסוֹ — אֵשֶׁת גִּיסוֹ אֲסִירָא, וְאִשְׁתּוֹ שַׁרְיָא,

Rabbi Yitzḥak Nappaḥa said: Actually, Rabbi Yosei is referring to the latter clause of the mishna, and the explanation is as follows: This is referring to one who married his brother-in-law’s wife, and that case is referring to one who married his brother-in-law’s betrothed. Alternatively, this involves a situation where his betrothed and his brother-in-law went overseas, whereas that concerns a situation when his wife and his brother-in-law went abroad. And the first tanna said: It is no different whether the ones who left were his wife and his brother-in-law, and it is no different whether they were his betrothed and his brother-in-law. Either way his brother-in-law’s wife is forbidden to her husband and his own wife or betrothed is permitted to him.

וְקָאָמַר לֵיהּ רַבִּי יוֹסֵי: אִשְׁתּוֹ וְגִיסוֹ, דְּלֵיכָּא לְמֵימַר תְּנָאָה הֲוָה לֵיהּ בְּנִשּׂוּאִין, דְּאֵינוֹ פּוֹסֵל עַל יְדֵי אַחֵר — אֵינוֹ פּוֹסֵל עַל יְדֵי עַצְמוֹ. אֲרוּסָתוֹ וְגִיסוֹ, דְּאִיכָּא לְמֵימַר תְּנָאָה הֲוָה לֵיהּ בְּקִידּוּשִׁין, וּפוֹסֵל עַל יְדֵי אֲחֵרִים — אַף פּוֹסֵל עַל יְדֵי עַצְמוֹ.

Rabbi Yitzḥak Nappaḥa continues his interpretation. And Rabbi Yosei said to the first tanna: If his wife and his brother-in-law left, in which case it cannot be said that he had a condition with regard to his marriage to his wife, i.e., that the finalization of the marriage was pending on the fulfillment of some condition, everyone would realize that his marriage to her sister was a mistake and she is therefore permitted to his brother-in-law. Consequently, as he does not disqualify another, he does not disqualify himself either. If, however, it was his betrothed and his brother-in-law who left, when it can be mistakenly said that he had a condition with regard to his betrothal and the condition was unfulfilled, his brother-in-law’s wife is therefore prohibited from returning to his brother-in-law. And therefore, as he disqualifies others he also disqualifies himself, and his betrothed is forbidden to him.

אָמַר רַב יְהוּדָה אָמַר שְׁמוּאֵל: הֲלָכָה כְּרַבִּי יוֹסֵי. מַתְקֵיף לַהּ רַב יוֹסֵף: וּמִי אָמַר שְׁמוּאֵל הָכִי? וְהָאִתְּמַר: יְבָמָה, רַב אָמַר: הֲרֵי הִיא כְּאֵשֶׁת אִישׁ, וּשְׁמוּאֵל אָמַר: אֵינָהּ כְּאֵשֶׁת אִישׁ. וְאָמַר רַב הוּנָא: כְּגוֹן שֶׁקִּדֵּשׁ אָחִיו אֶת הָאִשָּׁה, וְהָלַךְ לוֹ לִמְדִינַת הַיָּם, וְשָׁמַע שֶׁמֵּת אָחִיו, וְעָמַד וְנָשָׂא אֶת אִשְׁתּוֹ.

§ Rav Yehuda said that Shmuel said: The halakha is in accordance with the opinion of Rabbi Yosei. Rav Yosef strongly objects to this: And did Shmuel actually say this? But wasn’t it stated that they disputed the status of a yevama: Rav said that she is like a married woman, and Shmuel said that she is not like a married woman. And Rav Huna said that this dispute concerns a case where his brother betrothed a woman and that brother went off overseas, and the one left behind heard that his brother was dead and he arose and married his brother’s wife, in levirate marriage, and subsequently the missing brother returned.

דְּרַב אָמַר: הֲרֵי הִיא כְּאֵשֶׁת אִישׁ — וַאֲסוּרָה לַיָּבָם, וּשְׁמוּאֵל אָמַר: אֵינָהּ כְּאֵשֶׁת אִישׁ, וְשַׁרְיָא לֵיהּ!

As Rav said that she is like a married woman who married another man based on testimony that her husband was dead and is therefore forbidden to the yavam, i.e., to her first husband, who is called the yavam after his brother married her. And Shmuel said that she is not like a married woman, and is permitted to him. This apparently contradicts Rav Yehuda’s ruling in the name of Shmuel that the halakha is in accordance with the opinion of Rabbi Yosei, as here too people might mistakenly think that the original betrothal included an unfulfilled condition and she should therefore be forbidden to him as the wife of his brother.

אֲמַר לֵיהּ אַבָּיֵי: וּמִמַּאי דְּכִי אָמַר שְׁמוּאֵל הֲלָכָה כְּרַבִּי יוֹסֵי — אַדְּרַבִּי יִצְחָק נַפָּחָא קָאָמַר? דִּלְמָא אַדְּרַבִּי אַמֵּי קָאָמַר! וְאִי נָמֵי אַדְּרַבִּי יִצְחָק נַפָּחָא, מִמַּאי דְּאַ״פּוֹסֵל״,

Abaye said to Rav Yosef: And from where do you know that when Shmuel said that the halakha is in accordance with the opinion of Rabbi Yosei, he was speaking of the explanation of Rabbi Yitzḥak Nappaḥa with regard to Rabbi Yosei’s opinion? Perhaps he was speaking of the explanation of Rabbi Ami, that Rabbi Yosei is referring to the difference between one who married by permission of the court and one who did so based on the testimony of witnesses. And even if one accepts the claim that Shmuel’s ruling endorses the interpretation of Rabbi Yitzḥak Nappaḥa, from where do you know that he was referring to the clause: One who disqualifies?