1) TWO "ISURIM" THAT TAKE EFFECT SIMULTANEOUSLY
QUESTION: The Gemara (end of 35b) cites the Beraisa in which Rebbi Shimon teaches that "Ein Isur Chal Al Isur," once an object is prohibited with one Isur, it cannot become prohibited again with another Isur. Rebbi Shimon rules that one who eats Neveilah on Yom Kippur is exempt from punishment for eating on Yom Kippur, because the Isur of eating on Yom Kippur does not take effect upon the pre-existing Isur of Neveilah.
RASHI (DH ha'Ochel) writes that even if the animal was alive when Yom Kippur arrived, and on Yom Kippur itself it died and became a Neveilah, the animal is forbidden only because of the Isur of Neveilah and not because of the Isur of eating on Yom Kippur. Rashi explains that this is because the animal was already forbidden because of another Isur before Yom Kippur arrived -- the Isur of Ever Min ha'Chai.
TOSFOS (DH ha'Ochel) and other Rishonim ask that Ever Min ha'Chai applies only when the animal is alive. At the moment the animal dies, the Isur of Ever Min ha'Chai departs and the new Isur of Neveilah takes effect. At that moment, the new Isur of Neveilah and the Isur of Yom Kippur take effect simultaneously. Rebbi Shimon, who says "Ein Isur Chal Al Isur," agrees that two Isurim can take effect on one object when they take effect simultaneously. "Ein Isur Chal Al Isur" applies only when one Isur precedes the other Isur. Why, then, does the Isur of Ever Min ha'Chai prevent the Isur of Yom Kippur from taking effect at the moment the animal dies on Yom Kippur? Both Isurim -- that of Yom Kippur and that of Neveilah -- should take effect simultaneously!
ANSWER: Rashi apparently understands that two Isurim take effect simultaneously only when the causes for the Isurim occur at the same time. In the case of the animal that dies on Yom Kippur, the cause for the Isur of Yom Kippur occurs earlier, when the day begins (at which time the animal was prohibited due to Ever Min ha'Chai), but the cause for the Isur of Neveilah occurs later, when the animal dies. In such a case, the two Isurim do not take effect simultaneously.
The logic behind this is as follows. The Isur that takes effect now (Neveilah) comes as a result of an active cause (the death of the animal). Since the Isur of Ever Min ha'Chai no longer applies at this moment, nothing stops the Isur of Neveilah from taking effect. In contrast, the Isur of Yom Kippur was caused earlier (by the onset of the day) but something (the Isur of Ever Min ha'Chai) prevented it from taking effect. The Isur of Yom Kippur has to "wait" for the moment at which there is no other Isur on the animal in order for it to take effect. If any Isur remains on the animal, such as the Isur of Neveilah, the Isur of Yom Kippur remains suspended.

36b----------------------------------------36b

2) FULFILLING THE MITZVAH OF MATZAH WITH "MA'ASER SHENI"
QUESTIONS: Rebbi Akiva states that a person does not fulfill the Mitzvah to eat Matzah when he eats Matzah made from wheat of Bikurim. His reasoning is that the Matzah used for the Mitzvah must be Matzah that may be eaten in all parts of Eretz Yisrael ("Ne'echal b'Chol Moshavos"). Bikurim may be eaten only in Yerushalayim.
The Gemara continues and asks that for the same reason, one should not be able to fulfill the Mitzvah with Matzah of Ma'aser Sheni, because it, too, must be eaten in Yerushalayim.
RASHI (DH Af Ma'aser Sheni) explains that Ma'aser Sheni that is Tahor may not be redeemed once it arrives in Yerushalayim. It must be eaten in Yerushalayim, and it may not be redeemed and eaten in any other place. This is because the Rabanan enacted that once the produce of Ma'aser Sheni arrives inside the Mechitzos, or boundaries, of Yerushalayim, it may not be redeemed ("Mechitzos Liklot mid'Rabanan," Makos 20a).
The Gemara answers that the Torah specifically allows one to fulfill the Mitzvah with Matzah of Ma'aser Sheni. The Torah uses the word, "Matzos" (in the verse, "You shall eat Matzos"), in the plural form, when it could have said simply, "Matzah." This implies that the Mitzvah may be fulfilled with another type of Matzah -- Matzah of Ma'aser Sheni.
The Gemara asks why the Derashah of "Matzos" includes Matzah of Ma'aser Sheni and not Matzah of Bikurim. The Gemara answers that it is logical that the Torah intends to include Matzah of Ma'aser Sheni, because there is a way to permit Ma'aser Sheni to be eaten in all parts of Eretz Yisrael, which is one of the requirements of Matzah Shel Mitzvah. The Gemara explains that Ma'aser Sheni may be eaten in all parts of Eretz Yisrael when it has become Tamei and must be redeemed (and it may be redeemed even in Yerushalayim).
Rashi's words here are difficult to understand.
(a) Rashi writes that the rule of "Mechitzos Liklot" is only mid'Rabanan. However, the Gemara asks that just as one may not fulfill the Mitzvah with Matzah of Bikurim, one also should not be able to fulfill the Mitzvah with Matzah of Ma'aser Sheni, because the verse requires that the Matzah be able to be eaten in all places. According to Rashi's explanation, Ma'aser Sheni may be eaten in all places, mid'Oraisa! The Torah permits one to redeem Ma'aser Sheni even after it has arrived in Yerushalayim. It was the Rabanan who enacted that Ma'aser Sheni may not be redeemed once it has arrived in Yerushalayim. Why does the Gemara ask that one should not be able to fulfill the Mitzvah of Matzah with Ma'aser Sheni, if, mid'Oraisa, Ma'aser Sheni may be eaten in all parts of Eretz Yisrael? It must be that the Gemara's question follows the opinion that "Mechitzos Liklot" is mid'Oraisa, and not mid'Rabanan as Rashi says. (TOSFOS DH d'Amar)
(b) Even if Rashi finds a way to justify why an extra source is necessary to teach that Ma'aser Sheni may be used for the Mitzvah of Matzah, even though mid'Oraisa Ma'aser Sheni may be redeemed and eaten in all parts of Eretz Yisrael, what forces Rashi to say that the Gemara follows the opinion that "Mechitzos Liklot" is mid'Rabanan? Rashi should explain simply that the Gemara follows the opinion that "Mechitzos Liklot" is mid'Oraisa, as Tosfos says. (TZELACH)
(c) Even if Rashi has a logical basis to exclude types of Matzah that the Rabanan decreed may not be eaten in all places, the Beraisa itself contradicts this assertion. The Beraisa says that the word "Matzos" teaches that Ma'aser Sheni may be used for the Mitzvah. Why does a verse teach that Ma'aser Sheni can be used, if the only reason why it should not be used is because the Rabanan decreed that it cannot be eaten in all places? The Rabanan's decree came after the verse in the Torah was written! (See OR CHADASH. REBBI AKIVA EIGER leaves this question unanswered and writes, "Tzarich Iyun Gadol.")
ANSWERS:
(a) A logical argument could be made that the Isur d'Rabanan not to redeem Ma'aser Sheni is able to affect whether Ma'aser Sheni fits into the Torah's category of something that can be eaten in all places. Once the Rabanan decreed that Ma'aser Sheni in Yerushalayim may not be redeemed, their decree effectively made Ma'aser Sheni something that mid'Oraisa is unable to be eaten in all places, and thus mid'Oraisa one cannot use it for Matzah. This logic is suggested by Tosfos himself (38a, DH Aval). Rashi gives a similar line of reasoning (35b, DH Tavul mid'Rabanan) when he says that an Aveirah d'Rabanan can prevent one from fulfilling the Mitzvah of Matzah because of "Mitzvah ha'Ba'ah b'Aveirah," even though the Aveirah is only mid'Rabanan. (See Insights to Pesachim 35:1, in the name of the Maharsha, who shows that this logic does not always apply. An Isur d'Rabanan will not necessarily make the Derashah of "Lo Sochal Alav Chametz" apply. Each case needs to be analyzed separately. See DEVAR SHMUEL.)
(b) In the Gemara in Makos (20a) which Rashi cites, no mention is made of any opinion that maintains "Mechitzos Liklot" is mid'Oraisa. The Gemara there mentions only the opinion of Rava, who says that this law is mid'Rabanan, and no one there seems to argue. Accordingly, perhaps Rashi understands that there is no opinion that it is mid'Oraisa.
Other Rishonim, including Tosfos, understand that this point -- whether "Mechitzos Liklot" is mid'Rabanan or mid'Oraisa -- indeed is the subject of debate there. They explain that the question of the Gemara there is whether the Rabanan decreed "Mechitzos Liklot" or whether it is a law d'Oraisa. Rashi, however, learns that the only question there is how stringent the Rabanan were in their decree of "Mechitzos Liklot." This is also clear from the words of Rashi in Bava Metzia (53b, DH Mechitzah et seq.).
Tosfos, who maintains that the status of the law of "Mechitzos Liklot" is debated in Makos, is able to explain that the Gemara here follows the view that it is mid'Oraisa. Rashi, however, maintains that there is no opinion that says that the law is mid'Oraisa, and therefore he explains that the reason why Ma'aser Sheni cannot be redeemed in Yerushalayim is because of the enactment of the Rabanan of "Mechitzos Liklot."
(c) The DEVAR SHMUEL suggests that when the Gemara derives from the word "Matzos" that one may fulfill the Mitzvah with Matzah of Ma'aser Sheni, it does not mean that the Torah specifically teaches that one may eat Ma'aser Sheni to fulfill the Mitzvah of eating Matzah. As mentioned above, this verse is not necessary to teach that Matzah of Ma'aser Sheni may be used, because according to Torah law, Ma'aser Sheni may be eaten in all places, and thus it is fit for the Mitzvah of Matzah. Rather, the Derashah of "Matzos" teaches other laws (mentioned at the end of the Daf). Only incidentally does it teach that had there been a prohibition against eating Ma'aser Sheni in all places, one still would be permitted to eat it for the Mitzvah of Matzah, as long as there would be some way to eat it in all places.
(REBBI AKIVA EIGER, who leaves this question unanswered, perhaps does not accept this answer because the words of the Gemara are very inexact according to this answer. The Gemara asks, "Why do you see fit to [use the Derashah to] include Ma'aser Sheni and not Bikurim?" These words imply that the Gemara is asking how we know which of these two to include, Ma'aser Sheni or Bikurim. The Gemara assumes that the Derashah of "Matzos" includes only one or the other. According to the explanation of the Devar Shmuel, however, the Derashah does not relate directly to Ma'aser Sheni. According to his approach, the Gemara should ask instead, "Mai Ta'ama" -- "What is the reason you are including Ma'aser Sheni," and not, "How do you know which one to include.")
3) REDEEMING MA'ASER SHENI
QUESTION: The Gemara asks in what way is Ma'aser Sheni considered fit to be eaten in all places ("Ne'echal b'Chol Moshavos"). The Gemara answers that Ma'aser Sheni is fit to be eaten in all places, because if it becomes Tamei, it may be redeemed and eaten outside Yerushalayim.
Why does the Gemara not give a much simpler case in which Ma'aser Sheni may be eaten in all places? Ma'aser Sheni may be eaten outside Yerushalayim whenever one redeems it before he brings it to Yerushalayim, whether or not it has become Tamei!
ANSWERS:
(a) TOSFOS RABEINU PERETZ explains that the Gemara's discussion refers only to Ma'aser Sheni that was already brought into Yerushalayim. Such Ma'aser Sheni cannot be redeemed unless it becomes Tamei.
This also appears to be the approach of RASHI (DH Af Ma'aser Sheni b'Yerushalayim) and TOSFOS (38a, DH O).
(b) The MAHARAM CHALAVAH explains that when one redeems Ma'aser Sheni before he brings it into Yerushalayim, he is still required to bring the money to Yerushalayim, because the money has the sanctity of Ma'aser Sheni. The produce that was redeemed loses its sanctity of Ma'aser Sheni. Consequently, when one eats that produce outside of Yerushalayim, he is not eating Ma'aser Sheni! On the other hand, when Ma'aser Sheni has already entered Yerushalayim and it becomes Tamei and is redeemed, the produce itself retains the status of Ma'aser Sheni, since it entered the confines of Yerushalayim. In such a case, redemption of the Ma'aser Sheni does not transfer its sanctity to the money, but merely permits the Ma'aser Sheni to be taken out of Yerushalayim.

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