1) TERUMAH AND BIKURIM ARE "ASURIM L'ZARIM"
QUESTION: The Beraisa (end of 52b) lists differences between the laws of Terumah and Bikurim and the laws of Ma'aser. The Beraisa says that the punishment for one who intentionally eats Terumah and Bikurim is death, and one who eats them unintentionally must pay an extra fifth. The Beraisa adds that Terumah and Bikurim are forbidden for Zarim (non-Kohanim) to eat.
The second statement of the Beraisa seems entirely unnecessary. The Beraisa has already said that one who eats Terumah and Bikurim is punishable by death, and one who eats them unintentionally must pay an extra fifth. The Beraisa clearly refers to a non-Kohen who eats Terumah and Bikurim. Why does it need to add that a non-Kohen may not eat Terumah and Bikurim?
ANSWERS:
(a) RASHI (DH v'Asurim l'Zarim) writes that there is no reason why the Beraisa needs to add that Terumah and Bikurim are forbidden to Zarim. It adds this statement only because of the contrast which the end of the Beraisa teaches: "Mah she'Ein Ken b'Ma'aser" -- "this is not the case for Ma'aser." If the Beraisa would not have explicitly stated that Terumah and Bikurim are forbidden to Zarim, one might have thought that Zarim are forbidden from eating Ma'aser as well, although they are not punished with the same strict punishments as those who eat Terumah and Bikurim. The Beraisa therefore says that Zarim are forbidden from eating Terumah and Bikurim so that it can contrast Ma'aser with Terumah and Bikurim and teach that Zarim are permitted to Ma'aser.
TOSFOS (DH v'Asurim l'Zarim) points out that the Mishnah in Chalah (1:9) uses this same terminology, but does not mention Ma'aser at all. Why does the Mishnah in Chalah mention that Zarim may not eat Terumah and Bikurim, if it has already said that they are punished by death for eating it intentionally, and they must pay an extra fifth if they eat it unintentionally?
(b) Tosfos quotes the Yerushalmi which answers that the Beraisa means that Zarim are not allowed to eat even a Chatzi Shi'ur (less than the minimum amount for which one is punishable) of Terumah or Bikurim. Tosfos apparently understands that this is true according to both Rebbi Yochanan (Yoma 74a), who maintains that the Torah prohibits one from eating a Chatzi Shi'ur of any forbidden item, and Reish Lakish, who maintains that a Chatzi Shi'ur is prohibited only mid'Rabanan. According to Rebbi Yochanan, the Beraisa means that a Chatzi Shi'ur of Terumah or Bikurim is forbidden mid'Oraisa. According to Reish Lakish, the Beraisa means that a Chatzi Shi'ur is forbidden mid'Rabanan.
The RASHBA questions this explanation. Why should the Beraisa need to point out that one may not eat less than the amount punishable by Torah law? Everyone agrees that a Chatzi Shi'ur of every Isur is forbidden, either mid'Oraisa (Rebbi Yochanan) or mid'Rabanan (Reish Lakish)! Why does the Beraisa need to mention the prohibition of Chatzi Shi'ur specifically with regard to Terumah and Bikurim?
The Rashba answers that the prohibition of Chatzi Shi'ur is derived from the verse that prohibits Chelev (forbidden fats; see Yoma 74a). One might have thought that the prohibition against eating a Chatzi Shi'ur applies only to Isurim which apply to every Jew equally, but not to Isurim which apply only to some Jews and not to others, such as the Isur of Terumah and Bikurim to Zarim. The Beraisa therefore mentions specifically that a Chatzi Shi'ur of Terumah and Bikurim is forbidden to Zarim. (Y. Montrose)

53b----------------------------------------53b

2) DOES AN "ISUR D'RABANAN" RENDER AN OBJECT A "DAVAR SHE'EIN LO MATIRIN"?
QUESTION: The Beraisa (53a) states that fruit of Ma'aser Sheni worth less than a Perutah which came into Yerushalayim and then went out is Batel b'Rov. The Gemara explains that when the Beraisa says that the Ma'aser Sheni "went out" it refers to when the walls of Yerushalayim were razed after the Ma'aser Sheni entered Yerushalayim. The fruit has the status of a "Davar she'Ein Lo Matirin," since the Rabanan decreed that once fruit of Ma'aser Sheni enters Yerushalayim it no longer may be redeemed. Such an object can become Batel, in contrast to a "Davar she'Yesh Lo Matirin" (an object which can become permitted or used in a permitted manner) which does not become Batel.
The SHA'AGAS ARYEH (ha'Chadashos #12) asks that this Gemara seems to contradict the RAMBAN's explanation for why Chametz is not Batel during Pesach. The Ramban explains that since the Chametz will be permitted after Pesach, it is considered a "Davar she'Yesh Lo Matirin" during Pesach and therefore is not Batel. Even though Chametz owned by a Jew during Pesach is prohibited mid'Rabanan after Pesach ("Chametz she'Avar Alav ha'Pesach"), apparently the Ramban still considers it a "Davar she'Yesh Lo Matirin" because mid'Oraisa it is permitted after Pesach. However, the Gemara here calls Ma'aser Sheni a "Davar she'Ein Lo Matirin" due to the fact that it is prohibited mid'Rabanan from being redeemed once it has entered the walls of Yerushalayim! Why does the Ramban consider an Isur d'Rabanan inconsequential when determining whether something is a "Davar she'Yesh Lo Matirin"?
ANSWER: The SHA'AGAS ARYEH answers that the Rabanan's decree of "Chametz she'Avar Alav ha'Pesach" -- that Chametz owned by a Jew during Pesach is forbidden after Pesach -- was instituted as a stringency, not a leniency. Hence, Chametz is considered a "Davar she'Yesh Lo Matirin" and is not Batel even though it will continue to be prohibited after Pesach, mid'Rabanan. In contrast, the Rabanan's prohibition against redeeming Ma'aser Sheni once it has entered the walls of Yerushalayim was not intended to be solely a stringency. Therefore, the Ma'aser Sheni is considered to have no way of becoming permitted (since a person is not expected to transgress a decree of the Rabanan) and thus it can become Batel. (Y. Montrose)