Even though Beis Shamai and Beis Hillel argued about Tzaros, sisters (below, 4:1), a Get Yashan (the couple was secluded between the writing and the giving of the Get), a Safek Eshes Ish (Mi'un of a Nesu'ah), one who is Mekadesh with Shaveh Perutah (Beis Shamai say that the Shi'ur is a Dinar), one who divorced his wife and lodged with her in an inn, Beis Shamai did not refrain from marrying women of Beis Hillel, and Beis Hillel did not refrain from Beis Shamai.

Rather, they conducted with truth and Shalom - "veha'Emes veha'Shalom Ehavu";

Question: They argue about Mamzerus, and you say so (that they did not refrain from marrying women of the other school)?!

Question: What is the case [in which Beis Hillel hold that the child is a Mamzer, and Beis Shamai argue? Beis Shamai are always more stringent!]

Answer: One man was Mekadesh a woman with a Shaveh Perutah, and another was Mekadesh her with a Dinar. According to Beis Shamai, she is Mekudeshes to the second; if she had a son from the first, he is a Mamzer. According to Beis Hillel, she is Mekudeshes to the first; if she had a son from the second, he is a Mamzer.

Answer #1 (R. Yakov bar Acha citing R. Yochanan): Beis Shamai agree to Beis Hillel to be stringent (if a woman was Mekudeshes with a Perutah, they consider her a Safek Eshes Ish).

Objection: If so, Beis Hillel should [be willing to marry] women of Beis Shamai, for [Beis Shamai] agree to [stringencies of Beis Hillel], but Beis Shamai should not marry women of Beis Hillel, for [Beis Hillel] do not agree to [stringencies of Beis Shamai]!

Answer #2 (R. Heila citing R. Yochanan): Both of them did like the Halachah (like Beis Hillel. Beis Shamai did not follow their own teachings.)

Question: If they did like the Halachah, why does a Mishnah say that [water flowed through a hollow rock into a Mikveh, and] Beis Shamai sent and widened the opening, for Beis Shamai require that the majority be open?!

Answer: (R. Yosi bei R. Bun): Until a case came to Beis Hillel (before they ruled about it), Beis Shamai would be involved (e.g. they sent to widen the opening before Beis Hillel ruled about it). Once a case came to Beis Hillel, Beis Shamai would not be involved (rule against Beis Hillel. We explained this like PNEI MOSHE.)

Support (R. Avmari): Does the Mishnah say that they were Metamei Taharos retroactively? No, [Beis Shamai sent to widen the opening. They were concerned only] from now and onwards.

(R. Yosi bei R. Bun): Rav and Shmuel [argued about this]. One of them said that and both of them did like the Halachah (like Beis Hillel), and one said that these followed their laws, and these followed their laws.

Question: They argue about Mamzerus, and you say so (that they followed their own laws? If so, how could they marry women of the other school)?!

Answer: Hash-m guarded that a case never occurred [in which Beis Shamai married someone from Beis Hillel who was Pasul according to Beis Shamai, or vice-versa. We explained this like HA'GAON RAV C. KANIEVSKY, SHLITA.]

This is like what was taught - whoever wants to be stringent on himself to conduct like the stringencies of Beis Shamai and the stringencies of Beis Hillel, it says about him "veha'Ksil ba'Choshech Holech." One who conducts like the leniencies of these and of these is called a Rasha;

Rather, one should do like the words of Beis Shamai - like their stringencies and their leniencies, or like the words of Beis Hillel - like their stringencies and their leniencies.

Limitation: This was before the Bas Kol (voice from Shamayim that announced that the Halachah follows Beis Hillel), but after the Bas Kol, the Halachah always follows Beis Hillel, and anyone who transgresses Divrei Beis Hillel is Chayav Misah.

(Beraisa): A Bas Kol came out, and said 'these and these are the words of Elokim Chayim, but the Halachah always follows Beis Hillel.

Question: Where did the Bas Kol come out?

Answer (Rav Bivi citing R. Yochanan): The Bas Kol came out in Yavneh.