1) A KORBAN WHOSE MEAT BECAME "TAMEI" -- THE OPINION OF REBBI YEHOSHUA
QUESTION: The Gemara discusses the opinion of Rebbi Yehoshua who says, "Im Ein Basar, Ein Dam" (literally, "if there is no flesh, there is no blood"). Since the Zerikah of the blood of the Korban permits the meat of the Korban to be eaten, if the meat becomes lost, destroyed, or Tamei, then the Zerikah may not be performed because it will not serve to permit anything. Similarly, if the Sheyarei ha'Minchah, the part of a flour-offering which is eaten, becomes Tamei or lost, then the Kemitzah (the act of collecting part of the flour and offering it upon the Mizbe'ach) may not be done.
The Gemara records three conflicting versions of Rebbi Yehoshua's opinion.
The Gemara (77b) first quotes the Mishnah in Menachos which states that if the Sheyarei ha'Minchah becomes Tamei or lost, then the Kemitzah cannot be done and thus the Korban Minchah is disqualified (Pasul).
Next, the Gemara quotes a Beraisa which states that if the meat of a Korban becomes Tamei, the Zerikah cannot be done, but, b'Di'eved, if the Zerikah was done, then the Zerikah works and the Korban is valid.
Finally, the Mishnah here (76b) teaches that if the meat of a Korban Tzibur becomes Tamei, then l'Chatchilah the Zerikah may be performed. The Gemara presumes that the Mishnah is expressing the opinion of Rebbi Yehoshua.
These three statements of Rebbi Yehoshua seem to contradict each other. The first statement says that even b'Di'eved, when the meat is Tamei, the Korban is disqualified. The second statement says that b'Di'eved, the Korban is valid, but not l'Chatchilah. The third statement (the Mishnah here) says that the Korban is valid even l'Chatchilah.
The Gemara answers that the Beraisa, which permits the Korban b'Di'eved, refers to the Korban of a Yachid, an individual. The Mishnah, which permits the Korban l'Chatchilah, refers to the Korban of a Tzibur. The Korban is permitted l'Chatchilah because of the principle, "Tum'ah Hutrah b'Tzibur" -- we ignore the Tum'ah of the meat altogether and consider it as though it is Tahor. For an individual, though, Tum'ah is not Hutrah, and thus the Zerikah may not be performed l'Chatchilah. Only if the Zerikah was performed already, then b'Di'eved the Korban is valid.
The Gemara, however, does not explain the Mishnah in Menachos. The Mishnah there states that the Korban Minchah is Pasul if the Sheyarei ha'Minchah became Tamei or lost. The Mishnah implies that it is Pasul even b'Di'eved, which is consistent with neither the Beraisa nor the Mishnah here. Why does the Gemara not answer that question? (MAHARSHA)
ANSWERS:
(a) The MAHARSHA says that the question from the Mishnah in Menachos does not bother the Gemara, and thus it does not address it. This may also be the intention of RASHI. Rashi (end of 77b, DH v'Od) writes that when the Mishnah in Menachos says that if the Sheyarei ha'Minchah becomes Tamei, then the Korban Minchah becomes Pasul, it does not necessarily mean that the Minchah is Pasul b'Di'eved. It may mean that it is Pasul only l'Chatchilah. Rashi means that the question from the Mishnah in Menachos is not so strong, and thus the Gemara does not bother to answer it.
(b) TOSFOS REBBI AKIVA EIGER and the RASHASH suggest as follows. The Gemara later (78b) says that Rebbi Yehoshua maintains that there is a difference between whether the meat (or Sheyarei ha'Minchah) became Tamei or became lost or destroyed. If the meat became lost or destroyed, then the Korban is Pasul even b'Di'eved. If, however, the meat became Tamei but is still present, then the Korban is not Pasul b'Di'eved, but only l'Chatchilah.
Based on this difference, we can understand why the Gemara does not bother to address the question from the Mishnah in Menachos. The Mishnah there discusses a case in which the Sheyarei ha'Minchah becomes either Tamei or lost. Perhaps the Mishnah says that the Korban Minchah is "Pasul" because of the case in which the Sheyarei ha'Minchah becomes lost. When the Sheyarei ha'Minchah becomes Tamei the Korban is Pasul only l'Chatchilah.
(c) TOSFOS REBBI AKIVA EIGER and the RASHASH give another answer based on the words of TOSFOS. Tosfos explains the Gemara's answer -- that one case refers to a Yachid and one refers to a Tzibur -- differently than Rashi. The reason why Rebbi Yehoshua allows a Korban Tzibur to be offered l'Chatchilah in a state of Tum'ah is because mid'Oraisa the Tzitz is Meratzeh for the Tamei meat (for "Achilos"). The meat is considered completely Tahor, and thus the Zerikah of the blood may be done for it. The only reason why a Korban Yachid cannot be offered l'Chatchilah when the meat is Tamei is because of a Gezeirah d'Rabanan. The Rabanan decreed that one should not rely on the Ritzuy of the Tzitz when the fats or flesh (Olin or Ochlin) of a Korban become Tamei. For a Tzibur, however, they did not enact this Gezeirah, because Tum'ah is Dechuyah for a Tzibur.
According to Tosfos, perhaps the Mishnah in Menachos is not a concern to the Gemara here, because it says only that the Korban is Pasul "k'Midas Rebbi Yehoshua," and not that Rebbi Yehoshua himself rules that the Korban is Pasul. The Mishnah there is discussing a Korban of a Yachid; it says that it is Pasul even b'Di'eved, because if there is no meat, the Zerikah may not be done, as Rebbi Yehoshua rules. Rebbi Yehoshua himself permits the Zerikah, b'Di'eved, in such a case, because he maintains that according to the Torah law, the Tzitz is Meratzeh for Olin and Ochlin (TOSFOS 78b, DH Ki Modeh). In contrast, the Tana of the Mishnah in Menachos maintains that even when the meat becomes Tamei, the Zerikah may not be done and the Korban is Pasul even b'Di'eved, because with regard to the Tzitz being Meratzeh he follows the view of Rebbi Yosi (and not Rebbi Yehoshua), who says that the Tzitz is not Meratzeh for foods. Accordingly, the Tana of that Mishnah is saying, "According to my opinion, that the Tzitz is not Meratzeh for foods, if I were to follow Rebbi Yehoshua who rules 'Im Ein Basar, Ein Dam' (if there is no meat, then the Zerikah may not be done), then when the meat and fats become Tamei, the Korban would be Pasul b'Di'eved." (See Tosfos 77b, DH Ela Peshita, who alludes to such an approach.)

78b----------------------------------------78b

2) THE MEAT OF A KORBAN PESACH THAT BECAME "TAMEI"
OPINIONS: The Mishnah teaches that the Korban Pesach may be offered only if its meat may be eaten. If the meat became Tamei, then the Korban may not be offered, because the purpose of offering the Korban Pesach is to eat it.
When any other type of Korban becomes Tamei, the Korban may be offered as long as even one k'Zayis of meat or fat is still Tahor. How much of the meat of the Korban Pesach must remain Tahor in order to permit the Korban to be offered?
(a) RASHI (62a, DH v'Iba'is Eima) says that at least one k'Zayis of meat must remain Tahor in order for the Korban to be offered.
(b) The Tosefta (Pesachim 6:2) says that enough meat must remain so that there is a k'Zayis for each participant in the Korban.
Rashi clearly argues with the opinion of the Tosefta. What is the basis for his argument?
Perhaps the opinions of Rashi and the Tosefta depend upon the argument between the Tana'im here. The Gemara (78b) suggests that according to Rebbi Nasan, the entire Jewish people may bring one Korban Pesach on behalf of everyone. It is still considered fit to eat, even though each person will receive far less than a k'Zayis of meat. It is considered fit for each person to eat because all of the others potentially could withdraw themselves from the Korban, leaving their portions of the meat to those who remain the owners of the Korban. According to that reasoning, whenever there remains a k'Zayis of Tahor meat of the Korban Pesach, everyone could withdraw except for one person, leaving him the k'Zayis to eat, and thus making the Korban Pesach fit to be eaten. This is the source for Rashi's opinion. The Tosefta does not agree with the Gemara's reasoning that since the others could withdraw it is considered fit to eat now, and therefore it requires that there be an actual k'Zayis for each participant.
RAV YECHEZKEL ABRAMSKY zt'l (in CHAZON YECHEZKEL) suggests a remarkable source for the Tosefta from the wording of the Mishnah here. The Mishnah states that if the meat becomes Tamei and the fat (Chelev) does not, the Korban Pesach is Pasul because it cannot be eaten. However, if the fat becomes Tamei and the meat does not, the Korban is not Pasul because it may be eaten. There is an interesting variation in the syntax of the Mishnah in the second case. In the first case, the Mishnah says, "If meat becomes Tamei and Chelev remains," the Korban is Pasul. In the second case, the Mishnah says, "If the Chelev becomes Tamei and the meat remains," the Korban is valid. The Mishnah adds the letter "Heh," the definite article "the," when it discusses the case in which the Chelev, and not the meat, becomes Tamei.
"Basar" ("meat"), without the prefix "Heh," refers to meat of any amount. Similarly, "Chelev" without the prefix "Heh" refers to Chelev of any amount. In contrast, "ha'Basar" ("the meat"), means all of the meat, and "ha'Chelev" means all of the Chelev.
This difference in syntax indicates that the first case of the Mishnah refers to a situation in which so many people are included in the Korban Pesach that when all of the meat is divided equally, there is exactly a k'Zayis of meat for each person, and no more. In such a case, if any amount, even a tiny amount, of the meat becomes Tamei, then the Korban Pesach becomes Pasul because each person now receives less than a k'Zayis.
In contrast, the second case of the Mishnah teaches that even if all of the Chelev becomes Tamei, as long as all of the meat remains Tahor, the Korban Pesach remains valid, because there is still a k'Zayis for each person, as the Tosefta stipulates.

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