1) THINKING THE WORDS OF SHEMA WITHOUT VERBALIZING THEM
QUESTION: Rebbi Meir states that a Ba'al Keri should think the words of Keri'as Shema in his heart but should not recite the words audibly. This implies that an ordinary person (who is not a Ba'al Keri) must say them aloud and may not merely think the words to himself. This contradicts Rebbi Meir's opinion earlier (15a), where he says that one may think the words of the Shema in his heart, even l'Chatchilah! How can these two statements of Rebbi Meir be reconciled?
ANSWER: The RITVA answers that in the Gemara earlier (15a), when Rebbi Meir says that one does not need to hear what he recites, he means that one fulfills his obligation when he speaks the words even though he does not hear what he says. He does not fulfill his obligation by merely thinking the words. (The ROSH comes to the same conclusion without asking the question.)
2) WHAT SHOULD A "BA'AL KERI" THINK IN HIS HEART?
OPINIONS: The Beraisa quotes Rebbi Meir who says that "a Ba'al Keri (who has not immersed in a Mikvah) should read Keri'as Shema but may not recite the blessings before or after the Shema. When he eats bread, he should recite the blessing afterwards (Birkas ha'Mazon) but not the blessing beforehand. He should think the words in his heart and not recite them audibly." When Rebbi Meir says that "he should think the words in his heart and not recite them audibly," is he referring to Keri'as Shema and Birkas ha'Mazon (but, with regard to the blessings for Keri'as Shema, he may not even think them in his mind), or is he referring to the blessings for Keri'as Shema (but Keri'as Shema itself and Birkas ha'Mazon he may actually recite audibly)?
(a) The PNEI YEHOSHUA writes that he should only think the words of Keri'as Shema and Birkas ha'Mazon and he may not recite them audibly. He may not even think the blessings for Keri'as Shema.
(b) The RASHASH and GILYONEI HA'SHAS (Rav Yosef Engel) understand that Rebbi Meir is saying that the Ba'al Keri may think the blessings, and he may audibly recite Keri'as Shema and Birkas ha'Mazon.
3) THE STUDENTS' BARREL OF WATER
QUESTION: Rav Nachman set up a barrel of nine Kavim of water for the students to purify themselves from Tum'as Keri. RASHI (DH Tiken Chitzva) explains that the water was for the students to pour over themselves "in the morning, prior to the reading of the Torah (Keri'as ha'Torah)." Why does Rashi not say that the water was to pour over themselves prior to the recitation of Keri'as Shema and Tefilah, which are said before the reading of the Torah?
ANSWER: SEFER BEIS YOSEF (Rav Avraham Direnfeld) explains that the "reading of the Torah" refers to learning Torah. The students would learn Torah in the morning before they said Keri'as Shema and Shemoneh Esreh.
4) HALACHAH: MUST A "BA'AL KERI" IMMERSE IN A MIKVAH NOWADAYS?
OPINIONS: The Mishnah and Gemara discuss at length the necessity of a Ba'al Keri to purify himself through immersion in a Mikvah in order to recite Keri'as Shema and blessings, and to learn Torah. What is our practice nowadays?
(a) RASHI (DH Amar Rava Hilchesa) writes that today we rely on the opinion of Rebbi Yehudah ben Beseirah who says that words of Torah cannot become Tamei (22a), and therefore a Ba'al Keri does not need to immerse himself. This is the opinion of many other Rishonim as well (see Tur OC 88).
(b) The RIF, RAMBAM (Hilchos Tefilah 4:6), and RA'AVAD explain that there were two different edicts. Ezra decreed that a Ba'al Keri may not learn Torah. The later Rabanan decreed that a Ba'al Keri may not recite Shemoneh Esreh. Ezra's decree was nullified, while the later decree was upheld in certain areas. In those places, a Ba'al Keri was required to purify himself before praying. The Rambam writes that in those areas, people were accustomed to "wash their entire bodies" in water in order to make themselves Tahor. The Kesef Mishneh explains that the Rambam means that the custom was for a Ba'al Keri to pour nine Kavim of water over himself in order to purify himself, but not necessarily to immerse himself in a Mikvah. The Tur records this practice.
HALACHAH: The SHULCHAN ARUCH (OC 88:1) mentions the original edicts, but writes that today we do not require immersion in a Mikvah or washing with nine Kavim for learning Torah or for Tefilah. The MISHNAH BERURAH (88:4), however, says that "men of [meritorious] deeds" do go to the Mikvah before Tefilah. However, if one is ill and became a Ba'al Keri unintentionally, he does not require immersion in a Mikvah, because the original edict never required such a person to immerse, as the Gemara concludes.
5) HALACHAH: IF ONE FOUND EXCREMENT IN THE PLACE WHERE HE PRAYED
The Gemara says in the name of Rava that if one finds excrement in the place where he prayed, "his prayer is an abomination," as the verse says, "The offering of an evil person is an abomination" (Mishlei 21:27).
TOSFOS (DH v'Ha Zevach) notes that this applies only when he prayed in a place in which he should have expected to find excrement. If he prayed in a place where, under normal circumstances, there was no reason to expect to find excrement on the ground, he did nothing wrong and he cannot be called "evil."
The SHULCHAN ARUCH (OC 76:8) rules like Tosfos. The MISHNAH BERURAH (76:28) writes that any place where little children are frequently found is an example of a place where one must be wary of finding excrement.
If one finds excrement in the place in which he prayed (that is, within four Amos of where he stood), he must repeat Shemoneh Esreh. The BI'UR HALACHAH (DH Tzarich Lachzor) adds that if a person is imprisoned in a place where there is excrement, he should not pray at all.
6) PRAYING NEAR URINE
QUESTION: The Gemara rules that if urine drips from a person while he is in the middle of Shemoneh Esreh, he must stop and wait until the flow ceases, and then he may resume his Shemoneh Esreh. Why is he permitted to resume his Shemoneh Esreh when there is urine on his body and clothing? The Mishnah (see 25b) states that one may not pray near urine!
(a) TOSFOS (DH Mamtin) cites the Gemara later (25a) that says that if urine is absorbed inside of something and is not wet enough to wet something else, then it is permissible to pray in its presence.
(b) Tosfos gives a second answer. It is forbidden mid'Oraisa to pray in the presence of the flow of urine as it exits the body. When the urine is no longer flowing from his body but is only resting in front of him on the floor (or on his clothes), the prohibition against praying in the presence of urine is only mid'Rabanan. The Rabanan did not enforce their decree not to pray in the presence of urine which appeared once he was already in the middle of Shemoneh Esreh. They only prohibited him from commencing to pray in the presence of urine.
(c) RABEINU YONAH explains that a person must indeed walk four Amos away from urine on the ground. Urine that is on his body and clothing, however, is only a small amount and does not smell (alternatively, it is covered by his outer garment, RITVA), and therefore the Rabanan did not prohibit him from praying in its presence.
HALACHAH: The SHULCHAN ARUCH (OC 78:1) rules that one may continue praying if the urine on his body is covered by his clothes. Even if it is not covered he may continue saying Shemoneh Esreh, since the Rabanan did not require him to interrupt his Shemoneh Esreh (like the first answer of Tosfos). If he was reciting Keri'as Shema, however, and urine soiled the outer layer of his clothing, he must interrupt and go change his clothes, since there is no requirement to stand in one place during the Shema (MISHNAH BERURAH OC 78:3).
The BI'UR HALACHAH adds that even though Tosfos does not require one to walk away from the puddle of urine on the ground, one should not rely on Tosfos' answer and he should walk away from the urine (based on the ruling of the Shulchan Aruch OC 90:27, which apparently is in accordance with the opinion of Rabeinu Yonah).