1) THE "KORBAN SIMCHAH" OF YOM TOV
OPINIONS: On every Yom Tov, a person is obligated to offer three types of Korbanos -- the Olas Re'iyah, the Shalmei Chagigah, and the Shalmei Simchah. The Olas Re'iyah and Shalmei Chagigah are offered once during the Yom Tov, and the Shalmei Simchah is offered and eaten every day of the Yom Tov in order to fulfill the Mitzvah of Simchas Yom Tov, experiencing the joy of eating the meat of Korbanos on Yom Tov.
Does the obligation to offer Shalmei Simchah require that one sacrifice a Korban Simchah, or does it require that one eat from the meat of a Shalmei Simchah? If the obligation is to eat from the Korban but not necessarily to sacrifice it, then one may fulfill his obligation by eating the meat of someone else's Korban Simchah. If, however, the obligation is to sacrifice a Korban Simchah, then one must bring his own Korban.
(a) The Gemara says that the obligation of Shalmei Simchah applies even to the night of Shemini Atzeres (and not the following day, according to Rashi here; see, however, Rashi to Sukah 48a, DH l'Rabos). The DEVAR SHMUEL cites an opinion that proves from here that the obligation is to eat the Korban and not to sacrifice it, because one may not offer a Korban at night.
TOSFOS (96b, end of DH Ta'un) indeed says that a person fulfills his obligation of Simchah by eating his friend's Korban, as the ARUCH LA'NER points out (Sukah 48a).
(b) RASHI (70a, DH Yotzei) is bothered by the question of how a person can fulfill his obligation of Shalmei Simchah with an animal that is not Chulin. The rule is that any obligatory Korban (such as the Shalmei Simchah) must be brought from Chulin and not from an animal that is already sanctified to be brought as a Korban (such as Ma'aser Behemah). Rashi answers this question by citing a verse from which we derive that the Shalmei Simchah is an exception, and it does not have to be brought from Chulin.
If the obligation is to eat the Shalmei Simchah, then there is no obligation per se to bring the Korban. Consequently, there should be no requirement that it be brought from Chulin! Something that must be eaten does not need to come from Chulin; only something that must be sacrificed must come from Chulin. From the words of Rashi it seems that there is an obligation to sacrifice a Korban for Shalmei Simchah, and one may not fulfill his obligation by eating from another's Korban. (M. KORNFELD)
How, though, does Rashi understand the Gemara that says that there is an obligation of Simchah even at night? The obligation of Simchah requires that one bring a Korban, and it is not possible to bring a Korban at night. It must be that Rashi understands that the Shalmei Simchah is similar to the Korban Pesach in that the entire purpose of the obligation to sacrifice the Korban is in order to eat it. There is both an obligation to sacrifice the Shalmei Simchah and to eat it. (RAV SHACH, zt'l, in AVI EZRI, Hilchos Chagigah 2:3, proposes a similar reasoning. See also DEVAR SHMUEL to Pesachim 109a; see also Insights to Chagigah 8:1 for a broader analysis of this question.)

71b----------------------------------------71b

2) "TO'EH B'DEVAR MITZVAH" WHEN ONE OFFERS A "SHELAMIM"
QUESTION: The Mishnah states that when a person slaughtered an animal l'Shem Korban Pesach on Shabbos Erev Pesach that was sanctified to be a Korban other than the Korban Pesach, and which was not even fit to be a Korban Pesach, he must bring a Korban Chatas to atone for his inadvertent desecration of Shabbos (the Melachah of Shechitah).
RASHI explains that the case involves a person who slaughtered a female sheep, or a ram that was two years old (neither of which is valid as a Korban Pesach), which was sanctified to be a Korban Shelamim. He slaughtered it inadvertently for the sake of the Korban Pesach. In what way is his act considered inadvertent (Shogeg)? Rashi says that he either forgot that it was Shabbos, or he thought that he was permitted to slaughter a Shelamim to be a Korban Pesach on Shabbos.
It is clear from the Mishnah that even Rebbi Yehoshua -- who maintains that one who mistakenly commits a sin while he thinks that he is fulfilling a Mitzvah, and he indeed fulfills a Mitzvah with his act ("To'eh b'Devar Mitzvah v'Asah Mitzvah") -- agrees that in this case the person is liable, because he was not "To'eh b'Devar Mitzvah" since he did not have in mind to bring a Korban Pesach. (It is obvious that he did not intend to offer the animal as a Korban Pesach, because everyone knows that the type of animal that he slaughtered cannot be used as a Korban Pesach.)
However, he should be considered "To'eh b'Devar Mitzvah v'Asah Mitzvah" in another respect. Although he did not intend to fulfill the Mitzvah to bring the Korban Pesach with his act, when he slaughtered the animal l'Shem Pesach he had intention to offer it as a Korban Shelamim. A Shelamim that is slaughtered she'Lo Lishmah is a valid Korban, and thus he indeed fulfills the Mitzvah to bring a Shelamim when he offers this Korban. Why, then, is he not considered "To'eh b'Devar Mitzvah v'Asah Mitzvah" with regard to the Shelamim? According to Rebbi Yehoshua, he should be exempt from a Chatas.
ANSWER: The Gemara later (72b) explains that Rebbi Yehoshua exempts one who is "To'eh b'Devar Mitzvah" only when that Mitzvah was able to be done only on that day (such as the Korban Pesach), and thus the person was hurried to do it, and as a result he became confused and made a mistake. A Shelamim, however, may be offered any time, and therefore the exemption of "To'eh b'Devar Mitzvah" does not apply to one who intends to offer the animal as a Shelamim.
This is Rashi's intention in the next case of the Mishnah (DH v'Im Re'uyin) when he says that "since he is hurrying to slaughter his Korban Pesach, he is exempt." (M. KORNFELD)
3) THREE CASES, THREE MISTAKES
QUESTION: The first part of the Mishnah enumerates three cases of inappropriate Shechitah on Shabbos. First, one who slaughtered the Korban Pesach she'Lo Lishmah (he slaughtered an animal, which was sanctified as a Korban Pesach, with intention to bring it as a different type of Korban) must bring a Chatas, because the Korban that he slaughtered is disqualified and thus he did not fulfill a Mitzvah with its Shechitah.
Second, one who slaughtered a Zevach Acher (she'Eino Ra'uy l'Pesach) l'Shem Pesach (he slaughtered an animal, which was not fit to be a Korban Pesach and which was sanctified as a different type of Korban such as a Shelamim, with intention to bring it as a Korban Pesach) must bring a Chatas because he was not "To'eh b'Devar Mitzvah" (see previous Insight).
Third, one who slaughtered a Zevach Acher (she'Ra'uy l'Pesach) l'Shem Pesach (he slaughtered an animal, which was fit to be a Korban Pesach but which was sanctified as a different type of Korban such as a Shelamim, with intention to bring it as a Korban Pesach) is exempt from a Chatas, according to Rebbi Yehoshua, because he was "To'eh b'Devar Mitzvah" when he thought that the animal that he slaughtered was a Korban Pesach.
In each of these cases, RASHI gives a different explanation for the person's mistake:
In the first case, Rashi says that the person mistakenly thought that he was permitted to slaughter a Korban Pesach on Shabbos with intention to bring it as any type of Korban.
In the second case, Rashi says that the person mistakenly thought either that he was permitted to slaughter any Korban l'Shem Pesach (similar to the person's mistake in the first case), or that the day was not Shabbos.
In the third case, in which the person slaughtered an animal that was fit to be a Korban Pesach, Rashi says that he thought that it actually was a Korban Pesach. He did not err in the law, but in the reality of the circumstances.
Why does Rashi give three different explanations for the three different cases? In the first case, Rashi says that the person erred in the Halachah when he thought that he was permitted to slaughter a Korban Pesach for the sake of any Korban. In the second case, Rashi says that the person erred either in the Halachah or in the day of the week. In the third case, Rashi says that the person erred in the identity of the animal; he thought that the animal was a Korban Pesach when it was actually a different Korban. (MAHARSHA, TOSFOS REBBI AKIVA EIGER on the Mishnayos)
ANSWER:
1. With regard to the first case, in which one slaughtered a Korban Pesach she'Lo Lishmah (with intention to bring it as another type of Korban), the MAHARSHA points out that the Gemara itself (72a) explains, like Rashi, that the person knew that it was a Pesach and did not mistakenly think that it was a different type of Korban. Had he thought that it was a Shelamim (and slaughtered it l'Shem Shelamim), it would have been a valid Korban Pesach and he would not be obligated to bring a Chatas, because "a mistaken Akirah is not an Akirah." This is why Rashi, in the first case, does not say that the person's mistake was that he thought the animal was a Shelamim (because in that case he would be exempt).
However, the Maharsha does not answer why Rashi does not say that the person forgot it was Shabbos. Perhaps Rashi does not suggest this possibility in the first case because if the person slaughtered the animal l'Shem Shelamim and he knew that it was a Pesach, it is obvious that the Korban is completely invalid (since a Pesach she'Lo Lishmah is invalid). There is no reason why he would deliberately attempt to ruin the Korban Pesach for no gain. Rather, it is obvious that the person thought that the Korban would be valid when slaughtered l'Shem Shelamim. Therefore, his mistake was in the Halachah, for he thought that the Korban would be valid when slaughtered l'Shem Shelamim. Since it must be that he erred in the Halachah of Lishmah, it is logical to say that the reason why he slaughtered it on Shabbos is also for that reason -- he thought that he was permitted to slaughter a Korban Pesach she'Lo Lishmah on Shabbos, because he thought that she'Lo Lishmah does not invalidate the Pesach.
2. With regard to the second case, it is obvious why Rashi mentions the two possible errors -- either the person erred in the Halachah and thought that he was permitted to slaughter a Shelamim l'Shem Pesach, or he forgot that it was Shabbos. Rashi does not say that the person thought that the animal was a Korban Pesach, because the Mishnah emphasizes that this is not a case of "To'eh b'Devar Mitzvah," for nobody makes such a mistake and thinks that this type of animal could be a Korban Pesach. Since he presumably knew that such an animal could not be a Korban Pesach, why did he slaughter a two-year-old animal l'Shem Pesach? It must be that he made one of the mistakes that Rashi mentions -- either he forgot that it was Shabbos, or he thought that slaughtering a Shelamim l'Shem Pesach on Shabbos is permitted. (See, however, Tosfos to 73a, DH l'Divrei, who apparently takes a different approach to this part of the Mishnah.)
3. With regard to the third case, in which one slaughtered a Shelamim, which was fit to be a Korban Pesach, l'Shem Korban Pesach, the Gemara (72a, see RASHI DH Ma'ali) says that one is considered to be "To'eh b'Devar Mitzvah" only when his mistake did not involve an "Akirah." That is, he was not trying to bring a Shelamim slaughtered she'Lo Lishmah, but rather he thought the animal was actually a Pesach. The reason for this assertion is presumably because the mistake must be made under pressure of time in order to be considered "To'eh b'Devar Mitzvah," as we mentioned earlier (see previous Insight). If he was aware that the Korban was a Shelamim, then he knew that he did not need to offer the Korban today, and thus he was not rushed to do this Mitzvah. Therefore, the person's mistake in this case must have been that he thought the animal was a Korban Pesach. Accordingly, he also thought that its Shechitah could be performed on Shabbos. For this reason Rashi explains, in the third case, that his mistake was that he thought the animal was a Korban Pesach. (M. KORNFELD)

OTHER D.A.F. RESOURCES
ON THIS DAF