WHAT IS DOCHEH SHABBOS?
Question (Rav Ashi): Even though R. Eliezer considers Simchah on Yom Tov to be Reshus, his opinion is difficult!
On Yom Tov even Melachah is permitted for Reshus, but Shevus is not - on Shabbos, Melachah is permitted only for [certain] Mitzvos, all the more so Shevus is not permitted!
Answer: R. Eliezer holds that Chachamim were more stringent [to decree Shevus] regarding Reshus than regarding Mitzvos.
(Beraisa - R. Eliezer): Machshirei (preparations for a) Mitzvah after slaughter (Rashi - cleaning the innards; Tosfos - Haktarah of Chelev, even though it could be done on Motza'ei Shabbos) are Docheh Shabbos, even though the [primary] Mitzvah was already done - all the more so Machshirei Mitzvah before slaughter are Docheh!
Question #1 (R. Akiva): Chachamim did not forbid Machshirei Mitzvah after slaughter, because slaughter was already Docheh Shabbos, but perhaps they forbade Machshirei Mitzvah before slaughter!
Question #2 (R. Akiva): Also, perhaps the Korban will be found to be Pasul, and retroactively he was Mechalel Shabbos!
Objection: If so, we should not slaughter for the same reason!
Affirmation: Indeed, R. Akiva first asked Question #2, and R. Eliezer refuted it [like we did]; then R. Akiva asked Question #1.
(Mishnah - R. Akiva): Haza'ah is Tochi'ach (disproves this)...
(Beraisa - R. Eliezer): Akiva - you challenge me [and deny an explicit verse with a ridiculous Kal va'Chomer] from slaughter?! Your death should be through slaughter!
R. Akiva: Do not deny what you taught to me - Haza'ah is only Shevus, yet it is not Docheh Shabbos!
Question: If R. Eliezer taught this, why did he retract?
Answer #1 (Ula): R. Eliezer taught that Haza'ah is not Docheh Shabbos for [enabling a Kohen to eat] Terumah, since [separation of] Terumah itself is not Docheh Shabbos [and the Terumah can be eaten after Shabbos];
R. Akiva asked him from Terumah - Shevus is not Nidcheh for a Mitzvah;
R. Eliezer thought that he asks from Haza'ah for Pesach.
Rejection (Rabah - Beraisa - R. Akiva): Haza'ah of a Tamei Mes Tochi'ach - if his seventh day fell on Shabbos which was Erev Pesach, Shevus is not Nidcheh for a Mitzvah!
Conclusion: This shows that R. Akiva asked about Haza'ah for Pesach!
Reiteration of Question (k): If R. Eliezer taught this, why did he argue [with R. Akiva and say that it is Docheh Shabbos]?
Answer #2: R. Eliezer forgot what he was taught about this; R. Akiva was trying to remind him.
Question: Why didn't R. Akiva explicitly remind him?
Answer: He holds that it is improper to explicitly tell one's Rebbi that the Rebbi forgot.
WHO MUST ENABLE HIMSELF TO BRING PESACH
Question: Why doesn't Haza'ah Docheh for the sake of Pesach - it is mere movement of water!
Answer (Rabah): This is a decree, lest one carry it four Amos in Reshus ha'Rabim.
Question: R. Eliezer should permit, for he says that Machshirei Mitzvah are Docheh (l'Chatchilah one may carry in Reshus ha'Rabim to enable bringing Pesach)!
Answer: That is only for a person who is already able and obligated to do the Mitzvah - here, the person is not able or obligated until after Haza'ah.
(Rabah): According to R. Eliezer, one may heat water [on Shabbos] for a healthy baby to [bathe him to] strengthen him for Milah that day, but one may not heat water to strengthen a weak baby in order to circumcise him, for now he cannot be circumcised.
Objection (Rava): If the baby is healthy, why does he need hot water?!
(Rava): Rather, all babies are considered sick (need hot water) regarding Milah; [if hot water was not prepared before Shabbos,] one may not heat water on Shabbos for Milah, for the baby is not ready.
Question (against Rabah - Abaye - Beraisa - R. Eliezer): If an Arel does not circumcise himself [on Erev Pesach], he is Chayav Kares [for not bringing Pesach].
He is not ready, yet he is Chayav Kares - this shows that he is obligated!
Answer #1 (Rabah): [An Arel is unlike a Tamei!] R. Eliezer holds that we do not slaughter Pesach and do Zerikah for one who is [now] Tamei Sheretz [or Tamei Mes on the seventh day];
Regarding any Tum'ah that detains an individual to Pesach Sheni, the Tzibur brings Pesach b'Tumah;
An individual is obligated to enable himself to bring Pesach only if a Tzibur [like him] would be required;
If a Tzibur was [mostly] Arelim, they must circumcise themselves - therefore, an individual must do so, if he does not he is Chayav Kares;
If a Tzibur was Tamei Mes, they need not do Haza'ah, for they may bring Pesach b'Tumah - therefore an individual [who did not do Hotza'ah and could not bring Pesach] is exempt.
Question (Rav Huna brei d'Rav Yehoshua): Pesach Sheni is not incumbent on a Tzibur; yet it is incumbent on an individual!
Answer (Rava): There is different, for the Tzibur brought Pesach Rishon.
Objection (Beraisa) Question: Perhaps one is Chayav Kares only if he was Tahor and close [to the Mikdash on Pesach Rishon] - what is the source to include [people who were unable to bring Pesach, i.e.] an Arel, a Tamei Sheretz or other Temei'im?
Answer: "Veha'Ish" includes these.
The Tana must hold that we do not slaughter and do Zerikah for one who is Tamei Sheretz - otherwise, he is like a Tahor!
Inference: Even though he cannot bring Pesach [in his current state], he is obligated [to immerse and bring Pesach], even though a Tzibur is not obligated (they may bring b'Tum'ah)!
Answer #2 (to Question (h) - Rava): Rather, R. Eliezer holds that we slaughter and Zorek for a Tamei Sheretz - the same applies to a Tamei Mes on his seventh day;
Haza'ah is needed only to enable him to eat the meat [at night] - eating is not Me'akev (therefore, Haza'ah is not Docheh).
Question (Rav Ada bar Ahavah): If he may not do Haza'ah, the slaughter was Lo l'Ochlav (he may not eat it)!
Answer (Rava): Lo l'Ochlav is for one who is sick or too old, who cannot eat - a Tamei [who could become Tahor by evening] could eat, he merely needs to fix himself!
WHICH MACHSIRIM ARE DOCHEH SHABBOS?
(Mishnah - R. Akiva): The general rule is [any Melachah which could be done before Shabbos is not Docheh].
(Rav Yehudah): The Halachah follows R. Akiva.
It was taught similarly regarding Milah:
(Mishnah - R. Akiva): The general rule is, a Melachah [for the sake of Milah] overrides Shabbos only if it cannot be done before Shabbos.
(Rav Yehudah): The Halachah follows R. Akiva.
Rav Yehudah needed to say this about both Mishnayos:
Had he taught only regarding Pesach, one might have thought its Machshirim [possible from before Shabbos] are not Docheh, for 13 covenants were not made over it, unlike Milah [but all Machshirei Milah would be permitted];
Had he taught only regarding Milah, one might have thought that its Machshirim are not Docheh because there is no Kares [for not circumcising on day eight], but all Machshirei Pesach would be permitted, since there is Kares for not bringing it.
WHEN IS CHAGIGAH OF THE 14TH BROUGHT?
(Mishnah) Question: When is Pesach accompanied by Chagigah [of the 14th, a Shelamim]?
Answer: It is brought when Pesach is brought on a weekday, in Taharah, and it is [too] small [to satiate the Chaburah], but not when Pesach is brought on Shabbos, b'Tum'ah, or is large [enough for the Chaburah].
Chagigah may be brought from flock or cattle, from sheep and goats, from male or females; it may be eaten for two days and one night.
(Gemara) Question: What was taught [previously] that prompted our Tana to ask about Chagigah?
Answer: He taught that carrying it and bringing it [from outside the Techum] are not Docheh Shabbos - it is brought only when Pesach is brought on a weekday, in Taharah, and it is small.