Contradiction (Mishnah #1): If two of four brothers were married to sisters and they died, the surviving brothers do Chalitzah.

In our Mishnah, why may one do Yibum?

Answer: There are two explanations why Mishnah #1 forbids Yibum. Neither applies here.

Explanation #1: Yesh Zikah (it is as if both sisters are Mekudashos to each brother).

Explanation #2: It is forbidden to Mevatel the Mitzvah of Yibum. (If we allow Yibum, perhaps Reuven will do Yibum with one and Shimon will die, and her sister will be exempt without Yibum or Chalitzah, for she is Achos Ishto of Reuven!)

In our Mishnah, each can say that he does Yibum with his Yevamah (and he has nothing to do with her sister)!

(Mishnah): If they both did Yibum, they may keep their wives.

(Shila - Beraisa): This is even if they are Kohanim.

Question: What is the reason?

Answer: The Isur for a Kohen to marry a Chalutzah is only mid'Rabanan. Chachamim did not forbid a Safek (if the Kohen really did Yibum, the Chalitzah that preceded it was meaningless.)

Objection: The Isur is mid'Oraisa!

(Beraisa): "And a divorced woman (is forbidden to a Kohen)" includes a Chalutzah!

Answer: The Isur is only mid'Rabanan; the verse is only an Asmachta.

(Mishnah): The Mitzvah is for the oldest brother to do Yibum. If a younger brother did Yibum, it is valid.

(Gemara - Beraisa): "And the firstborn..." - the Mitzvah is for the oldest to do Yibum;

"That will give birth" excludes an Ailonis, who cannot give birth;

"Yakum Al Shem Achiv "- for inheritance.

Question: Perhaps this commands to name the child like the deceased?

Answer: It says here, "Yakum Al Shem Achiv", like it says elsewhere, "Al Shem Acheihem Yikar'u b'Nachalasam". Just like there "Shem" refers to inheritance, also here.

"His name will not be wiped out" excludes a Seris, whose name is wiped out (even had he not died, he could not have children).

(Rava): Everywhere else in the Torah, a verse does not depart from its simple meaning. Here, a Gezeirah Shavah entirely uproots the simple meaning.

Question: Without the Gezeirah Shavah, how could one think that the Mitzvah is to name the child after the deceased? Who would be commanded about this?

If the Yavam were commanded, it should have said 'Yakum Al Shem Achicha (your brother)'!

If Beis Din were commanded, it should have said 'Yakum Al Shem Achi Aviv (his father's brother)'!

Answer: The Torah would instruct Beis Din to tell the Yavam to call the child after the deceased.

The Gezeirah Shavah teaches not to understand this way. (Rather, it discusses inheritance.)

Question: The Beraisa taught that the oldest is commanded to do Yibum. We should say that only a firstborn does Yibum!

Answer: This cannot be, for then we would not need the verse exempting Eshes Achiv she'Lo Hayah b'Olamo from Yibum.

Objection (Rav Achai): Perhaps this exclusion applies when the newborn brother is a firstborn to his mother!

Answer: The Torah made Yibum dependent on inheritance, which is only from the father.

Question: Perhaps Yibum applies only when there is a firstborn (and then, any brother may do Yibum)!

Answer: "And one of them died" connotes that either (of the two brothers) died, even the firstborn, and it says to do Yibum.

Question: Perhaps (to fulfill "And the firstborn..." we must say that) this is only when a younger brother died, and the firstborn does Yibum!

Answer: If so, we would not need a verse exempting Eshes Achiv she'Lo Hayah b'Olamo.

Suggestion: Perhaps the Yibum of a younger brother is valid only when there is no firstborn!

Rejection: "When brothers will live together" equates the brothers (any may do the Mitzvah).

Question: We should say that when there is a firstborn, the Mitzvah is on the oldest; when there is no firstborn, there is no preference. A Beraisa teaches otherwise!

(Abaye Kashisha - Beraisa): The Mitzvah is for the oldest to do Yibum. If he declines, we ask his younger brother. If he declines, we return to the oldest.

Answer: The oldest is like a firstborn. Just like a firstborn is first to do Yibum, also the oldest (even if he is not a firstborn) is first.

Suggestion: We should say that a firstborn who does Yibum inherits the deceased, but a regular brother who does Yibum does not!

Rejection: Even a regular brother fulfills "Yakum Al Shem Achiv".

Question: Why did the Torah specify the firstborn?

Answer: This diminishes his inheritance of the deceased;

Just like a firstborn gets an extra portion only from Muchzak (what his deceased father already had), not from Ra'uy (what was destined to come to him), also, a Yavam.

(Mishnah): If one was suspected of Bi'ah with a slave or Nochris and she converted, he should not marry her. If he did, he may stay married;

If Reuven was suspected of Bi'ah with a married woman, and they (Beis Din) made her husband divorce her, even if Reuven married her; he must divorce her.

(Gemara) Inference: If she converts, the conversion is valid.

Contradiction (Beraisa - R. Nechemyah): If one converted to marry a woman or man, or to receive food or authority from the king, the conversion is invalid;

If one converted to be saved from lions, because of a dream, or in the days of Mordechai and Esther (when people feared the Yisraelim), the conversion is invalid, unless he converts nowadays.

Objection: This cannot be!

Contradiction: Rather, it must be like nowadays (when surely it is not for authority).

Answer: R. Yitzchak bar Shmuel said that the Halachah follows the opinion that all these are valid conversions.

Question: If so, he should be allowed to marry her!

Answer: One should not cause people to speak ill about him;

(Rav Asi): (The Mishnah forbids marrying her due to) "Remove from yourself stiff talk and ill rumors".

(Beraisa): We do not accept converts in the era of Mashi'ach. Similarly, we did not accept in the days of David and Shlomo.

(R. Elazar): We learn from "Hen Gur Yagur..." (only one who dwells with us (he converts) when Hash-m is not with us, i.e. in our poverty, will receive a portion with us in the world to come).

(Mishnah): If one was suspected of Bi'ah with a married woman...

(Rav): This applies only if there were witnesses.

Rav Sheshes: Rav must have been sleeping when he said this!

Question (Rav Sheshes against Rav - Beraisa): If Reuven was suspected of Bi'ah with a married woman, and Beis Din made her husband divorce her, and she married David and was divorced, and Reuven married her, he may keep her.

Question: What is the case?

If witnesses saw that Reuven had Bi'ah with her, even if she married someone else in between, which stops the rumors, she is forbidden to Reuven!

Answer: Rather, there are no witnesses. They may stay married only because she married someone else in between and ceased the rumors. This is unlike Rav!

Answer #1: Rav holds that even if she didn't get married in between, they can stay married. We force them to separate only when there are witnesses.

The Beraisa teaches that even when she married David in between, l'Chatchilah she may not remarry Reuven.

Question (Beraisa): This applies when she has no children. If she has children, they may stay married;

If there are witnesses of adultery, even if she has many children he must divorce her!

Answer #1: Rav establishes our Mishnah to be when there are witnesses, and she has children.

Question: What forced Rav to establish our Mishnah in such a case, to say that we force them to separate only when there are witnesses? He could have said that she has no children, and we force them to separate even without witnesses!

Answer (Rava): The Mishnah is difficult;

Question: Why does it say 'they made him divorce her'? It should say 'he divorced her'!

Answer: This teaches that Beis Din forced the divorce. Beis Din forces only when there are witnesses

Answer #2 (to Questions (d) and (f)): The Beraisos are like Rebbi (who says that we force without witnesses).