(Mishnah): If he sees b'Ones, or if there is a Safek...

(Rava): The Safek is not whether or not he had an emission;

Rather, he surely had an emission, but we are unsure if it was pure Zivah (which cancels previous clean days counted), or if there was semen with it (in which case it is not a clean day, but it does not cancel previous clean days).

Once he became a Zav, a Safek is Tamei (it is assumed to be Zivah).

(Mishnah): His semen is Tamei.

Question: In what respect is it Tamei?

Suggestion: It is Metamei one who touches it.

Rejection: This applies to everyone's semen!

Answer #1: Rather, it has Tum'as Masa (it is Metamei one who moves it).

Question: Which Tana says so?

Suggestion: It is R. Yehoshua:

(Beraisa - R. Eliezer): Semen of a Zav does not have Tum'as Masa;

R. Yehoshua says that it has, for surely it contains drops of Zivah.

Rejection: The Mishnah connotes that the semen itself has Tum'as Masa. R. Yehoshua says that only the Zivah inside does!

Answer #2 (Rav Ada bar Ahavah): If a Zav sees (has a flow of) Zivah (within 24 hours) after a seminal emission, the Zivah is considered like proper Zivah (we do not attribute it to the semen. This is why the Mishnah calls the semen 'Tamei'.)

Version #1 (Tosfos, Rosh) (Rav Papa): Rav Ada holds that if one who was Tahor sees Zivah after semen, we attribute it to weakness due to the semen. (But for a Zav, even Zivah b'Ones is considered Zivah.)

Question (Rava - Mishnah): A convert can become a Zav immediately after converting (even if he saw semen right before converting. We discuss one who was circumcised previously. If he was weak from Milah, this would be Ones!)

We should attribute the Zivah to his weakness (like a Yisrael who saw Zivah after semen! Rosh - a convert is even weaker, due to anxiety about accepting the Mitzvos.)

Version #2 (Rashi) (Rav Papa): Rav Ada holds that proper Zivah is due to weakness. A Zav is known to be weak, so we attribute the Zivah to his weakness. (If one who was Tahor sees Zivah after semen, we attribute it to the semen.)

Question (Rava - Mishnah): A (previously circumcised) convert can become a Zav immediately after converting (even if he saw semen just before converting).

We should attribute the Zivah to the semen, since he is not weak!

Answer (Rav Papa): There is conversion (accepting the yoke of Mitzvos) is the ultimate weakness! (end of Version #2)

Defense (of Answer #1, and Answer to Question (e:1)): The following Tana'im hold that semen of a Zav has Tum'as Masa:

(Beraisa): If a Zav sees semen within 24 hours of seeing Zivah, the semen has Tum'as Masa;

R. Yosi says, it is only if the semen comes on the same day as the Zivah.

Question: What do they argue about?

Answer: They give different answers to Shmuel's question:

Contradiction (Shmuel): It says "when a man will be Tamei, a nighttime emission" (i.e. if he was a Zav, and he had a seminal emission the night after seeing Zivah, it has Tum'as Masa);

It also says "he will immerse Lifnos Erev" (this suggests that semen is like Zivah until the day is Poneh (leaves, after 24 hours)!

R. Yosi learns from the first verse. Chachamim learn from the second.

Question: How do Chachamim expound the first verse?

Answer: The verse discusses the usual case. Emissions usually come at night.

(Mishnah - R. Nehorai): Shmuel was a Nazir.

It says about Shmuel "u'Morah (a razor) will not pass over his head". "Morah" is also said regarding Shimshon.

Just like Shimshon was a Nazir, also Shmuel.

R. Yosi: "Morah" refers to "Mora" (fear), that Shmuel will not fear people.

Objection (R. Nehorai): "Shmuel said 'how can I go? Sha'ul will hear and kill me'". This shows that he feared people!

(Gemara): Rav and Rav Huna instructed their sons to say Birkas ha'Mazon to exempt the others.

Inference: They hold that it is better to bless than to answer Amen.

Question (Beraisa - R. Yosi): The one who answers Amen is greater than the one who blesses;

R. Nehorai: We find so regarding war. The weak ones fight first, and the victory is credited to the strong ones that finish.

Answer: Rav and Rav Huna hold like the following Tana.

(Beraisa): Both the one who blesses and the one who answers Amen get reward. Reward is paid first to the one who blesses.

(R. Elazar): Chachamim increase Shalom in the world - "All your children will know (will be Talmidim of) Hash-m; great will be the Shalom of your children."