1) A "SAFEK TUM'AH" WHEN BRINGING THE KORBAN PESACH
QUESTION: The Mishnah states that a person involved in a search and rescue mission for someone buried under a pile of stones may appoint an agent to offer his Korban Pesach for him. Even though the missing person may be found dead, and thus the searcher will be Tamei, at the moment that the Korban Pesach is brought he is considered Tahor. Therefore, if his Korban Pesach was brought before he discovered the corpse, he does not have to bring a Pesach Sheni.
The Gemara stipulates that this applies only if the pile of stones in which he searched was long and horizontal. As such, it can be assumed that he did not hover over the corpse before the Korban Pesach was slaughtered. If, however, the stones were in a circular configuration, then presumably he hovered over the corpse -- and became Tamei as an Ohel over a Mes -- before the Korban Pesach was slaughtered. In such a case, his Korban is ineffective and he is required to bring the Pesach Sheni.
RASHI explains that in the case of a long, horizontal pile of stones, he is not assumed to be Tamei at the time that his Korban is offered, because his status is in a state of doubt. He does not bring a Pesach Sheni because he might have already fulfilled his obligation with the first Korban. However, he is also not considered definitely Tahor. Rather, his status is in doubt, and the doubt does not require that he bring another Korban Pesach.
Although he has a Chazakah that he is Tahor (because he certainly was Tahor until the time that the doubt arose), he cannot rely on the Chazakah, because once the corpse was found, the searcher became definitely Tamei. Therefore, his "Chezkas Tahor" conflicts with his present state of Tamei, and thus his status remains a Safek.
The RASHASH asks why Rashi says that there is a Safek whether the searcher fulfilled the Mitzvah of Korban Pesach or not. There are clear rules for cases of Safek Tum'ah. In Reshus ha'Yachid, a Safek Tum'ah is viewed as definitely Tamei, while in Reshus ha'Rabim it is viewed as definitely Tahor. In what case does Rashi say that the person remains with a Safek? The pile of stones was most likely a Reshus ha'Yachid, and therefore he should be definitely Tamei. If the pile of stones was in a Reshus ha'Rabim, then he should be definitely Tahor. Either way, his status should not be a Safek.
ANSWER: In this case, the question is not one of Safek Tum'ah at all. It is clear that he became Tamei at a certain point. The subject of the question is not one of Tum'ah, such as the status of objects that he touched before it was known for certain that he was Tamei. Rather, the question here is whether he fulfilled his obligation to bring the Korban Pesach or not. Since the consequences of the doubt have nothing to do with the laws of Tum'ah, the normal rule of Safek d'Oraisa l'Chumra applies, and not the rules of Safek Tum'ah. (RAV ELAZAR MAN SHACH, zt'l, in AVI EZRI, Hilchos Korban Pesach 5:10)
2) "BAMOS YACHID" AND "BAMOS TZIBUR"
QUESTION: Rebbi Shimon derives from the verse, "You may not slaughter the Pesach in one of your gates" (Devarim 16:5), that during a time when Bamos are prohibited one who brings a Korban Pesach upon a Bamas Yachid (a privately-owned altar) transgresses a Lo Ta'aseh.
RASHI asks why Rebbi Shimon applies this prohibition only to a Bamas Yachid, and not to a Bamas Tzibur (a publicly-owned altar). Rebbi Shimon should have said that there is also a Lo Ta'aseh to bring a Korban Pesach on a Bamas Tzibur during a time when Bamos are prohibited. (Even though the verse implies only a Bamas Yachid, as it says "in one of your gates," Rashi apparently views it as illogical to differentiate between a Bamas Yachid and a Bamas Tzibur during a time when all Bamos are forbidden.)
Rashi answers that at the time that Bamos were forbidden, there was no such thing as a Bamas Tzibur. (Apparently, if a Tzibur built a communal Bamah, it was considered only a Bamas Yachid.) Rashi adds that after Shiloh was destroyed, Bamos (both Yachid and Tzibur) became permitted until the Beis ha'Mikdash was built. Once the Beis ha'Mikdash was built, all Bamos, including Bamos Tzibur, became forbidden again.
In light of Rashi's answer, it is difficult to understand the basis of his question. It must be that Rashi assumed that even during the times when Bamos were forbidden, it was permitted to have a Bamas Tzibur. Therefore, it should have been forbidden by a Lo Ta'aseh to offer a Korban Pesach upon a Bamas Tzibur.
However, if that is Rashi's assumption, then his question remains inexplicable. If it was permitted to have a Bamas Tzibur when Bamos Yachid were prohibited, then it certainly was permitted to bring a Korban Pesach on it. In fact, it was a Mitzvah to bring a Korban Pesach on it (Megilah 9b). Perhaps Rebbi Shimon specifically mentions the prohibition with regard to a Bamas Yachid, because there is no prohibition against offering a Korban Pesach on a Bamas Tzibur.
Moreover, why does Rashi answer that when Bamos were forbidden there was no Bamas Tzibur? When the Aron ha'Kodesh was in Shiloh, Bamos Yachid were forbidden, and yet the Mizbe'ach in Shiloh was a Bamas Tzibur.
ANSWER: Rashi's intention is to clarify this very point -- the exact status of the Mishkan in Shiloh. Rashi asserts that the Mizbe'ach in Shiloh was not considered a Bamas Tzibur, but a Mishkan (therefore, even Korbanos that are not permitted on a Bamas Tzibur, such as Korbenos Chovah that do not have a set time, were offered in Shiloh; see Megilah 9b).
Rashi asks why Rebbi Shimon says that when Bamos are forbidden, there is a Lo Ta'aseh that forbids bringing the Korban Pesach upon a Bamas Yachid. This wording implies that there was a time when only Bamos Yachid were forbidden, while Bamos Tzibur were permitted. It appears that Rebbi Shimon specifies that to sacrifice the Pesach on a Bamas Yachid is forbidden with a Lo Ta'aseh, because Bamos Tzibur are permitted. This period must have been when the Mishkan stood in Shiloh, and Bamos were prohibited, but the Mishkan itself was used.
Rashi, however, does not accept this approach. Rather, he explains that Rebbi Shimon says that the Lo Ta'aseh applies only to a Bamas Yachid, because there cannot be a Bamas Tzibur at the time that Bamos are forbidden. Rebbi Shimon does not specify Bamas Yachid to imply that a Bamas Tzibur is permitted, but rather to show that there is no such thing as a Bamas Tzibur at a time when Bamos are forbidden. The Mishkan in Shiloh was not a Bamas Tzibur; it was a Mishkan. This, of course, also answers the second question. Rashi maintains that the Mishkan of Shiloh was not considered a Bamah, rather it was a full-fledged Mishkan.
This question of Rashi -- whether Shiloh had a status of a Bamas Tzibur or a Mishkan -- appears to depend on a variant text in a Tosefta in Zevachim (13:8). The Tosefta in Zevachim asks, "What is considered a Bamah Gedolah (Bamas Tzibur) at the time when Bamos are permitted?" It answers that wherever the Ohel Mo'ed is present without the Aron ha'Kodesh, it is a Bamas Tzibur. According to this reading, the Tosefta, like Rashi, assumes that a Bamas Tzibur can exist only when Bamos are permitted -- because a Bamas Tzibur, too, is a Bamah.
There is another version of that Tosefta (the text that the Aruch (Erech "Bamah") and Rabeinu Chananel had) which asks, "What is considered a Bamah Gedolah at the time when Bamos are forbidden?" According to this reading, it is clear that a Bamas Tzibur can exist even when a Bamas Yachid is prohibited. This must refer to the period of the Mishkan in Shiloh (at times when the Aron was not housed there, such as after the Aron ha'Kodesh was captured by the Pelishtim, or when it was moved for any other reason), since it is the only era when a Bamas Tzibur could have existed even though Bamos Yachid were prohibited.
The two variations of the Tosefta differ with regard to the status of the Mishkan in Shiloh, which existed at a time when Bamos Yachid were forbidden and the Ohel Mo'ed was present. Originally, the Aron was also present in Shiloh. At that time, Shiloh certainly was considered a Mishkan and not a Bamah. However, when the Aron was captured, Shiloh's status became subject to dispute. Either it reverted to the status of a Bamas Tzibur, or, since it was originally built with the Aron there, it remained a Mishkan (and was not a Bamah). (It is interesting to note that the Mishkan both in Nov and in Giv'on was built when the Aron was not present. See Rashi to Pesachim 38b, DH Zos Omeres.)
(The words of Rashi here contradict two theses of the MESHECH CHOCHMAH (Devarim 12:8). First, the Meshech Chochmah proposes that after the Aron was captured from Shiloh, Bamos Yachid were permitted. (As he points out, this appears to be the subject of a dispute in the Yerushalmi, Megilah 1:12.) Rashi here writes that Bamos Yachid were permitted only after Shiloh was destroyed. Second, the Meshech Chochmah writes that even before the Beis ha'Mikdash was actually built, while Giv'on still stood, Bamos Yachid were prohibited. Rashi writes that there was no period when a Bamas Tzibur existed but Bamos Yachid were prohibited.)