1)

(a)Our Mishnah lists 'Onso u'Sefeiko ve'Shichvas-Zar'o', which are Tamei once he is already a Zav. Rava defines 'S'feiko' (other than a Safek whether he had a sighting [of Zivus] or not) - when he had a Safek whether he saw Zivus or Shichvas-Zera.

(b)When the Tana mentions 'Shichvas-Zar'o', he cannot be referring to Tum'as Maga - because it is obvious that the Shichvas-Zera of a Zav after two sightings is Metamei, no less than that of a person who is not a Zav.

(c)We initially think that he cannot be referring to Tum'as Masa either because of a Machlokes between R. Eliezer and Rebbi Yehoshua in a Beraisa as to whether the Shichvas-Zera of a Zav is Metamei Tum'as Masa or not - and where even Rebbi Yehoshua only holds that it is, because of the possibility that it may contain drops of Zivus (but not the Shichvas-Zera itself - which our Mishnah appears to be talking about) ...

(d)... whereas Rebbi Eliezer holds - that he is Tahor anyway.

2)

(a)So Rav Ada bar Ahavah connects our Mishnah with the Mishnah in Zavin, where the Tana says - that someone who sees Zivus within twenty-four hours of Keri is not Metamei be'Zivah.

(b)When Rav Ada therefore says 'Lomar she'Ein Tolin Bah' he means - that that Mishnah is confined to the first two sightings of Zivus, but should he see his third sighting within those twenty-four hours, we do not attribute it to the previous sighting of Keri.

(c)

1. Rav Papa attempts to explain this logically - by ascribing the Mishnah in Zavin to the Zav's weakness (with which our Tana does not contend if he already had two sightings of Zivus).

2. Rava proves Rav Papa (and Rav Ada bar Ahavah) wrong from the very same Mishnah in Zavin, from the case cited there of the Ger she'Nisgayer - whose sighting of Zivus is counted (even it was the first or the second sighting after he saw Keri before converting). When he adds 'Ein L'cha Choli Gadol mi'Zeh', he means that according to Rav Papa and Rav Ada bar Ahavah, the Zivus should certainly be considered a sign of weakness, and ought not therefore to be counted (irrespective of the fact that he saw the Keri when he was still a Nochri).

(d)We therefore conclude that Keri precludes Zivus within twenty-four hours - due to the Pasuk "ve'Hayah Lif'nos Erev Yirchatz ba'Mayim" (which is a 'Gezeiras-ha'Kasuv').

3)

(a)Rava finally establishes 'Shichvas-Zar'o' in our Mishnah - with regard to Tum'as Masa, like we attempted to explain it above (but rejected).

(b)The Tana Kama of a Beraisa is Metamei the Shichvas-Zera of a Zav be'Masa within twenty-four hours. Rebbi Yossi says - until nightfall.

(c)Rava did not cite the Mishnah in Keilim which specifically lists the Shichvas-Zera of a Zav among the things that are Metamei be'Masa - because our Mishnah, as well as the Beraisa, are speaking about Shichvas-Zera which he saw close to the Zivus, whereas the Mishnah in Keilim is even speaking where he saw it later, within seven days.

4)

(a)Rebbi Yossi and the Tana Kama argue over Shmuel, who points out an apparent contradiction between the Pesukim "Ki Yih'yeh B'cha Ish Asher Lo Yih'yeh Tahor ... Mikreh Laylah" (because he is a Zav) [implying twenty-four hours] and "ve'Hayah Lif'nos Erev Yirchatz ba'Mayim" [which implies until nightfall].

(b)Rava explains that the Tana Kama stresses the first Pasuk, and Rebbi Yossi, the second.

(c)

1. The Chachamim will explain the Pasuk "Mikreh Laylah" - like Chazal often do, that the Torah mentions it (not to teach us anything, but) because it is normal to see Keri during the night.

2. And Rebbi Yossi will explain the Pasuk "ve'Hayah Lif'nos Erev ... " - to exempt Zivus that the Ba'al Keri sees within twenty-four hours (see Mesores ha'Shas).

5)

(a)The source of Rebbi Nehora'i in our Mishnah for saying that Shmuel was a Nazir from birth is - a 'Gezeirah-Shavah': "Morah" (Shmu'el - by the birth of Shmuel) "Morah" (Shoftim - in connection with Shimshon, whom the Navi specifically describes as a Nazir).

(b)Rebbi Yossi wants to explain the Pasuk "u'Morah La Ya'aleh al Rosho" - to mean that neither of them were ever frightened of any human-being (as if "Morah" was written with an 'Alef', rather than with a 'Hey').

(c)Rebbi Nehora'i disproves Rebbi Yossi however - from the Pasuk in Shmuel, which describes Shmuel's fear of Shaul (upon receiving instructions to go and crown David).

6)

(a)What Rav and Rav Huna meant when they advised their respective sons Chiya and Rabah 'Chatof u'B'rich' was - that they should try wherever possible, to be the one to Bensh Mezuman (which entails Benshing aloud on behalf of all present) because reciting a B'rachah takes precedence over answering 'Amein'.

(b)Rebbi Yossi says in a Beraisa - 'Gadol ha'Oneh Amein Yoser min ha'Mevarech', which seems to clash with this idea.

(c)Rebbi Nehora'i substantiates Rebbi Yossi's opinion - with the analogy of the foot-soldiers who defeat the enemy, yet the victory is ascribed to the cavalry who finish the job, a proof that 'everything goes after the conclusion'.

(d)So we conclude that Rav and Rav Huna follow the opinion of the Tana in another Beraisa - who says that even though the person reciting the B'rachah and the one who answers 'Amein' are ostensibly on a par with each other, it is the person who recited the B'rachah who is the first to be rewarded.

7)

(a)Rebbi Elazar Amar Rebbi Chanina learns from the Pasuk in Yeshayah "ve'Chol Banayich Limudei Hash-m ve'Rov She'lom Banayich" - that Talmidei-Chachamim increase peace in the world (see Agados Maharsha and Einei Shmuel).