Question: Regarding Shemoneh Esreh, we are not concerned that he be engaged in the same matter as the Tzibur!

(Mishnah): If, during Shemoneh Esreh, one remembers that he is a Ba'al Keri, he does not stop praying, rather, he says abridged blessings.

Inference: Had he not yet started, he should not start!

Answer #1: He must be engaged in Keri'as Shema with the Tzibur, for it contains accepting Ol Malchus Shamayim -- this does not apply to Shemoneh Esreh.

Rejection: Birkas ha'Mazon does not have acceptance of Ol Malchus Shamayim, yet our Mishnah says that a Ba'al Keri says it!

Answer #2: He must engage in Keri'as Shema and Birkas ha'Mazon, for they are mid'Oraisa; Shemoneh Esreh is only mid'Rabanan.

Question (Rav Yehudah): What is the source that mid'Oraisa one must bless after eating?

Answer: "V'Achalta v'Savata u'Verachta."

Question: What is the source that mid'Oraisa one must bless before learning Torah?

Answer: "Ki Shem Hash-m Ekra Havu Godel l'Elokeinu."

(R. Yochanan): A Kal va'Chomer from Birkas ha'Mazon teaches that mid'Oraisa one must bless after learning Torah; a Kal va'Chomer from Birkas ha'Torah teaches that mid'Oraisa one must bless before eating!

The Torah does not [explicitly] require blessing before eating, it requires blessing after eating; since it requires blessing before learning Torah, all the more so one must bless after learning Torah!

The Torah does not [explicitly] require blessing after learning Torah, it requires blessing before learning Torah; since it requires blessing after eating, all the more so one must bless before eating!

Objection #1: We cannot learn [to bless for] Torah from eating, for eating is different, because one physically benefits from eating!

Objection #2: We cannot learn [to bless for] eating from Torah, for Torah is different, because it gives one eternal life!

Objection #3 (Mishnah): He blesses after eating, but not before eating (for the latter is only mid'Rabanan).

R. Yochanan is refuted.

(Rav Yehudah): If one is unsure whether or not he said Keri'as Shema, he need not say it out of doubt;

If one is unsure whether or not he said Emes v'Yatziv, he must say it. (Tosfos - perhaps he did not mention Yetzi'as Mitzrayim, i.e. he is also unsure whether or not he said [Parshas Tzitzis in] Keri'as Shema.)

Question: What is the reason?

Answer: [He holds that] Keri'as Shema is mid'Rabanan, Emes v'Yatziv is mid'Oraisa.

Question (Rav Yosef): "Uv'Shachbecha uv'Kumecha" -- mid'Oraisa, one must say Keri'as Shema!

Answer (Abaye): That refers to learning Torah.

Question (Mishnah): A Ba'al Keri thinks about the Berachos before Shema and after (i.e. Emes v'Yatziv), but does not say them; he blesses after eating, but only thinks about the Berachah before eating.

If Emes v'Yatziv is mid'Oraisa, he should say it!

Counter-question: [If it is only mid'Rabanan,] why do we say it?

It is not in order to mention Yetzi'as Mitzrayim -- we already mentioned it in Shema!

Question: We should say Emes v'Yatziv and not Shema!

Answer: Keri'as Shema is preferable, for it has Kabalas Ol Malchus Shamayim and Yetzi'as Mitzrayim.

(R. Elazar): If one is unsure whether or not he said Keri'as Shema, he must say it;

If one is unsure whether or not he prayed Shemoneh Esreh, he need not pray again.

(R. Yochanan): If only we could pray the entire day (i.e. one should pray again out of doubt)!

(Rav Yehudah): If one was praying and remembered that he already prayed, he stops, even in the middle of a Berachah.

Question: But Rabah bar Avuha was asked about one who realized that he was saying a weekday Berachah during the Shabbos Shemoneh Esreh, and he answered that he should finish the Berachah (and complete Shemoneh Esreh of Shabbos)!

Answer: There it is different -- really, the person should say all the Berachos even on Shabbos; Chachamim did not place this obligation on him on Shabbos;

But if one already prayed, he need not pray again!

(Rav Yehudah): If one prayed and entered a synagogue where people are praying:

If he can pray for something new (Rambam - in every, or at least one, of the middle Berachos; Rema - a need that arose after his previous Shemoneh Esreh), he should pray with them; if not, not.

Rav Yehudah must teach both laws:

Had he only taught the first law, one might have thought that is only if both times he prayed by himself or with a Tzibur, but if one who prayed alone can now pray with a Tzibur, it is as if he did not pray;

Had he only taught the second law, one might have thought that is because he did not begin yet, but if he began, he must finish.

(Rav Huna): If one entered a synagogue where people are praying:

If he can begin and finish before the Shali'ach Tzibur (in his repitition of Shemoneh Esreh) will reach Modim, he should begin; if not, not (it is more important to bow with the Tzibur at Modim than to pray together with the Tzibur).

(R. Yehoshua ben Levi): If he can begin and finish before the Shali'ach Tzibur reaches Kedushah, he should begin; if not, not.

Question: What do they argue about?

Answer: Rav Huna holds that an individual (praying with a Tzibur) says Kedushah (therefore, we are not concerned if he cannot say it with the Tzibur), R. Yehoshua ben Levi holds that an individual does not say Kedushah.

Question (Rav Ada bar Ahavah): What is the source that an individual does not say Kedushah?

Answer: We learn from "v'Nikdashti b'Soch Bnei Yisrael" -- every matter of Kedushah needs ten men.

Question: How do we learn this from the verse?

Answer (Ravnai, brother of R. Chiya bar Aba): We learn from a Gezeirah Shavah "Toch-Toch":

It says here "v'Nikdashti b'Soch Bnei Yisrael," like it says about Adas Korach "mi'Toch ha'Edah." We learn "Edah-Edah" from "la'Edah ha'Ra'ah ha'Zos," which refers to the Meraglim;

Just like there, there were ten (evil Meraglim), also here there must be ten (Jews).

All agree that we do not interrupt Shemoneh Esreh to answer to Kedushah.

Question: Do we interrupt Shemoneh Esreh to answer "Yehei Shemo ha'Gadol Mevorach" (in Kaddish)?

Answer (Rav Dimi): One interrupts anything to answer "Yehei Shemo ha'Gadol Mevorach," even Ma'aseh Merkavah (Yechezkel's prophecy of Hash-m's chariot).

The Halachah does not follow Rav Dimi.

(Mishnah - R. Yehudah): He blesses before and after.

Inference: This implies that R. Yehudah permits a Ba'al Keri to say Divrei Torah.

Question: But R. Yehoshua ben Levi taught that he is forbidden!

It says, "v'Hodatam l'Vanecha uli'Venei Vanecha," followed by "Yom Asher Amadta" -- learning Torah is equated to Matan Torah;

Just as a Ba'al Keri could not participate in Matan Torah (this is why Bnei Yisrael were commanded to refrain from relations beforehand), he may not say Divrei Torah.

Suggestion: Perhaps R. Yehudah [argues because he] does not expound Semuchim (adjacency of verses).

Rejection: Rav Yosef taught that all expound Semuchim in Sefer Devarim (because it is mostly repetition), even the opinion that does not expound Semuchim in the rest of Torah.

Question: What is the source that R. Yehudah does not expound Semuchim in the rest of Torah?

Answer (Beraisa - Ben Azai): It says, "Mechashefah Lo Sechayeh," followed by "Kol Shochev Im Behemah Mos Yumas," to teach that a witch is stoned, just like one who commits bestiality.

R. Yehudah: Is the adjacency of the verses grounds to stone?!

Rather, Ov v'Yid'oni (sorcerers who conjure up the dead) are in the category of witches -- the Torah teaches that they are stoned, and this shows that all witches are stoned.

Question: What is the source that R. Yehudah expounds Semuchim in Sefer Devarim?

Answer (Beraisa - R. Eliezer): A man may marry a woman raped or enticed by his father or son;

R. Yehudah forbids him to marry a woman raped or enticed by his father.

(It is not clear why the Gemara cites this Beraisa instead of the Mishnah (Yevamos 97a) -- the following teaching was taught to explain R. Yehudah's opinion in the Mishnah!)

(Rav Gidal): R. Yehudah learns from "Lo Yikach... v'Lo Yegaleh Kenaf Aviv" -- a man may not take a woman who was intimate with his father.

Question: How do we know that it refers to a woman his father raped?

Answer: We know this from the previous verse -- "v'Nasan ha'Ish ha'Shochev Imah..."

(Summation of question: Since R. Yehudah expounds Semuchim in Devarim, he should connect "v'Hodatam l'Vanecha..." to "Yom Asher Amadta," and forbid a Ba'al Keri to learn Torah, just like at Matan Torah!)

Answer: R. Yehudah expounds this adjacency to teach something else that R. Yehoshua ben Levi taught:

(R. Yehoshua ben Levi): If one teaches Torah to his son, the Torah considers it as if he received Torah from Sinai:

It says "v'Hodatam l'Vanecha uli'Vnei Vanecha," followed by "Yom Asher Amadta... b'Chorev."

(If a man has two emissions of Zivah, he becomes a Zav, and he cannot become Tahor until counting seven clean days (i.e. free of emissions).)

Question (Mishnah): The following must immerse (before saying Divrei Torah) -- a Zav who had a seminal emission, a Nidah who discharged semen, and a woman who became Nidah after relations;

R. Yehudah exempts.

Summation of question: R. Yehudah exempts a Zav, for the decree did not apply to him when he first became Tamei (and now immersion will not be Metaher him), but he agrees that a [regular] Ba'al Keri must immerse!

Suggestion: Perhaps he exempts even a Ba'al Keri, and the Mishnah discusses a Zav to teach the extremity of Chachamim's opinion!

Rejection (Mishnah): A woman who became a Nidah after relations...

Question: Why was this clause taught?

Answer #1: It is to teach that Chachamim require her to immerse.

Rejection: They require even a Zav to immerse, even though he was Tamei before he was subject to Ezra's decree; they need not teach about one who was subject to Ezra's decree (on account of relations) before she became Tamei!

Answer #2: It is to teach that R. Yehudah exempts her.

Inference: He exempts her only because the immersion would not be Metaher her now (she still must wait seven days), but a Ba'al Keri is obligated!

Correction: In the Mishnah, R. Yehudah does not say that a Ba'al Keri blesses before and after, rather, he thinks (Meharher) the blessings in his mind.