(Mishnah): One's wife (Leah) went overseas. They told him that she died; he married her sister Rachel. Later, Leah returned. She may return to him, and he is permitted to Rachel's relatives, and Rachel is permitted to his relatives. If Leah later died, he may marry Rachel;

If they told him that Leah died, he married Rachel, and they told him that really, she died after the Nisu'in to Rachel, the first child (anyone conceived before Leah died) is a Mamzer, but the latter [child] is not.

R. Yosi says, anyone who forbids others forbids to himself. Anyone who does not forbid others, does not forbid to himself (this will be explained).

They told a man that his wife died, and he married her paternal sister. They told him that this wife died, and he married her maternal sister. They told him that this wife died, and he married her paternal sister. They told him that this wife died, and he married her maternal sister.

[If all were found to be alive,] he is permitted to his first, third and fifth wives, and they exempt their Tzaros (if he dies without children and one of them does Yibum or Chalitzah). He is forbidden to his second and fourth wives, and (if he dies without children) Yibum of either of them does not exempt her Tzarah;

If he had Bi'ah with the second wife after the first wife died, he is permitted to his second and fourth wives, and they exempt their Tzaros. He is forbidden to his third and fifth wives, and Yibum of either of them does not exempt her Tzarah.

(Gemara): It says "v'Shachav Ish Osah" - [a married woman's] Bi'ah forbids herself; [her husband's] Bi'ah with someone else (e.g. her sister) does not forbid her.

Question: (Why is she forbidden to her husband when she married based on false witnesses?) We should say also there "[v'At Ki Satis] Tachas Ishech" excludes Ones!

Answer (R. Masniyah): They decreed about something common. They did not decree about something uncommon. It is common for a man to go overseas. It is uncommon for a woman to go overseas.

(Beraisa - R. Yehudah): Beis Shamai and Beis Hillel agree that if one has Bi'ah with his mother-in-law, he forbids his wife [to himself]. What did they argue about? They argue about one has Bi'ah with his wife's sister. Beis Shamai say that he disqualified [his wife to himself]. Beis Hillel say that he did not disqualify.

(Talmidim citing R. Yochanan): R. Yehudah learns from "[if a man will take a woman and her mother...] ba'Esh Yisrofu Oso v'Es'hen."

1. Question: What is the case?

If it is regarding Sereifah - [this cannot be, for] only one of [the women] is burned (the first woman did not transgress)!

Answer: Im Eino Inyan (if it need not teach about) Sereifah, we expound it to teach about Isur. (Bi'ah with the latter forbids the former.)

Remark: This is like R. Akiva [who holds that Es'hen means 'both of them.' It cannot be] like R. Yishmael, for R. Yishmael taught "ba'Esh Yisrefu Oso v'Es'hen" - he and the second (even if his wife died, he is killed for his mother-in-law. The verse is not free to teach that Bi'ah with the mother-in-law forbids his wife. We explained this like PNEI MOSHE.)

Beis Shamai reasoned - in a place where a man with a light Isur had Bi'ah with a woman with a light Isur (this will be explained), he forbade the ones who forbid him - here, when a man with a severe Isur (Achos Ishto) had Bi'ah with a woman with a severe Isur (Achos Ishto), all the more so we should forbid the ones who forbid him (the man and his wife become forbidden to each other).

Question: What is this light Isur?

Answer #1 (R. Yochanan): It is the case of the beginning of our Perek (a woman remarried based on a false witness).

Question: Is that a light Isur?! Rather, it is severe (Eshes Ish)!

Answer: [It is called light] because [the latter] married her Derech Heter (we thought that her husband died).

Answer #2 (R. Hoshayah Rabah): This Beraisa discusses one who remarried his divorcee after she had Nisu'in (with a second man, and was widowed or divorced from him).

Question: Why did he say after she had Nisu'in? It is even after she became Mekudeshes!

Answer: [He said so] due to R. Yosi ben Kiper, for R. Yosi ben Kiper says that [one who remarried his divorcee after she was widowed or divorced] from Eirusin [with her second husband,] she is permitted [to her first husband].

Answer #3 (R. Liezer): The Beraisa discusses a Yevamah who fell to two Yevamim; one of them gave a Ma'amar, and then the other had Bi'ah with her.

Question: Why did he say after he gave a Ma'amar? [The first is disqualified] even if he did not give a Ma'amar (rather, he had Bi'ah with both of them)! Why did he say that he had Bi'ah with her? It is even if he did not had Bi'ah with her (rather, he gave a Ma'amar to both of them! - PNEI MOSHE)

Answer: It is due to Beis Shamai, and due to R. Gamliel (who holds that there is no Ma'amar after Ma'amar. Therefore, he needed to discuss Ma'amar and Bi'ah, in order that the Beraisa will be like all opinions);

(Beraisa - R. Shimon): Beis Shamai and Beis Hillel did not argue about one who has Bi'ah with his wife's sister, that he did not disqualify his wife [to himself]. What did they argue about? They argue about one has Bi'ah with his mother-in-law. Beis Shamai say that he disqualified [his wife to himself]. Beis Hillel say that he did not disqualify.

Beis Hillel reasoned that [initially,] a man is permitted to all women, and a woman is permitted to all men. When he was Mekadesh her, he forbade her and she forbade him;

The Isur that he forbade her is greater than the Isur that she forbade him. He forbids her to marry any man, and she forbade him only to her relatives.

There is a Kal v'Chomer. She, her Isur is greater, and if she transgressed her Isur (was Mezanah with another man) b'Shogeg, she is not forbidden to the one to whom she is permitted (her husband) - he, that his Isur is smaller, if he transgressed his Isur (was Mezanah with his wife's relative) b'Shogeg, all the more so he is not forbidden to the one to whom he is permitted (his wife)!

Question: This is b'Shogeg. What is the source that b'Mezid (he does not disqualify his wife to himself through Bi'ah with her relative)?

Answer: It says "Osah" - her Bi'ah forbids her. Another's Bi'ah does not forbid her.

(Imi, the father of Shmuel bar Imi, citing Rav Yehudah): The Halachah follows R. Shimon.

A case came in front of R. Mana (of one who had Bi'ah with his mother-in-law), and he removed her (forbade his wife to him);

It is not because he holds like R. Yehudah (who says that all agree that Bi'ah with his mother-in-law forbids his wife to him). Rather, she regularly used to come to her [daughter. There was concern lest he transgress with her again if he remains married.]