1) A KORBAN OFFERED BY AN OLD OR SICK KOHEN
QUESTION: The Gemara (109b) cites a Beraisa which says, "How do we know that a Kohen may come and offer his Korbanos at any time he desires? This is derived from the verse, 'And he may come whenever he desires... and serve in the name of Hashem' (Devarim 18:6-7)." RASHI (DH she'Bo) explains that if the Kohen vowed to bring a Korban or if he was obligated to bring a Chatas or Asham, he may come and offer his Korban even during a Mishmar of which he is not a member (that is, even at a time when it is not his turn to serve in the Beis ha'Mikdash). (See also MINCHAS CHINUCH 509:5, DH Hayah ha'Kohen Zaken.)
The Beraisa continues (110a) and says that if the Kohen is old or sick he may choose any Kohen to offer his Korban on his behalf. Rashi (DH v'Im) explains that the Beraisa refers to an old Kohen who is capable of performing the Avodah, as the Gemara later explains, but who is not capable to eat the meat of the Korban. Since he is fit to perform the Avodah himself, he is entitled to appoint a Shali'ach to perform the Avodah for him. However, as the Beraisa states, the meat and skin of the Korban must be given to the Kohanim of the present Mishmar. The Gemara explains that since he is not capable of eating the Korban himself (and any attempt to force himself to eat it would not be an act of eating but an act of "Achilah Gasah"), he may not appoint a Shali'ach to eat it on his behalf.
The Gemara implies that if a Kohen is unable to perform the Avodah himself, he may not designate an agent to perform the Avodah for him. Why, then, is any Yisrael (non-Kohen) able to appoint a Kohen as his Shali'ach to offer his Korban? The Gemara in Kidushin (23b) uses this logic to prove that the Kohanim are the agents of Hash-m and not the agents of Yisrael, and thus the Kohanim may offer the Korbanos on behalf of non-Kohanim. If, however, the Kohanim are the agents of Hash-m and not the agents of the ones offering the Korbanos, why should an old or sick Kohen who cannot perform the Avodah himself not be able to appoint a Shali'ach to bring his Korban on his behalf? Even though he is not capable of doing the Avodah, he still should be able to send his Korban with another Kohen, just as a Yisrael is able to have a Kohen offer his Korban on his behalf!
ANSWER: The NODA B'YEHUDAH (EH 2:9, DH u'Mah) answers that the Gemara does not mean that when one cannot do a certain act, he cannot appoint an agent to do that act. Rather, the Gemara discusses the specific question of whether a sick Kohen may have his Korban offered by a Kohen from a Mishmar other than the present Mishmar that is serving in the Beis ha'Mikdash.
The Noda b'Yehudah explains that the right to offer Korbanos normally belongs to the Kohanim of the Mishmar presently serving in the Beis ha'Mikdash. Nevertheless, the Torah gives to each Kohen the right to offer his own Korban even during the week of a Mishmar of which he is not a member. However, one may have thought that this right is non-transferable, and that the Kohen may not choose another Kohen (from a different Mishmar than the one presently serving in the Beis ha'Mikdash) to offer his Korban for him. Perhaps the Kohanim of the officiating Mishmar have the right to refuse to let him take away their privilege to offer the Korbanos by choosing an "outside" Kohen to offer his Korban for him.
The Gemara therefore teaches that a Kohen may appoint another Kohen who is not from the present Mishmar to bring his Korban. The reason why he is permitted to do this is that he may say to the Kohanim of the present Mishmar that they lose nothing from the fact that a Kohen from a different Mishmar is offering his Korban, since he could offer his Korban himself if he wanted to do so. This logic applies, however, only when he indeed is capable of offering his own Korban. If the Kohen is so old or sick that he is unable to do the Avodah himself, he cannot use this argument to justify his appointment of an "outside" Kohen, and he must give his Korban to the Kohanim of the present Mishmar. This is the intent of the Gemara's statement that if he cannot do the Avodah himself, he cannot appoint a Shali'ach to do it for him.
(The KOVETZ HE'OROS in Yevamos (72:2) seems to understand the Gemara like the Noda b'Yehudah. However, the MAHARATZ CHAYOS presents a different way to understand the Gemara.) (D. BLOOM)
2) ONE WHO STIPULATES AT THE TIME OF HIS MARRIAGE THAT HIS WIFE WILL NOT NEED TO PERFORM YIBUM WITH A REPULSIVE BROTHER-IN-LAW
QUESTION: The Mishnah (110a) discusses the case of a person who stole from a convert (who had no heirs) and swore falsely that he did not steal. Afterwards, he admitted his transgression, but the convert died before he had a chance to return the money to him. The Mishnah says that he must give the principle and the extra fifth to the Kohanim, and offer an Asham Gezeilos. The Mishnah continues and says that if the thief gave the money to the Kohanim of the Mishmar of that week but he died before they offered his Korban, the thief's heirs cannot receive the money back from the Kohanim.
Abaye infers from the Mishnah that the giving of the money to the Kohanim achieves half of the atonement for the thief, even if the Korban was not brought. If the giving of the money would not achieve any atonement at all, the Kohanim would be obligated to return the money to the thief's heirs. The thief certainly would not have given the money to the Kohanim if he would have known that no atonement would be gained from doing so, and thus his act of giving would be considered to have been done in error, and the Kohanim would have no right to keep the money. The fact that the Kohanim are not required to return the money shows that the giving of the money to the Kohanim achieves half of the atonement.
The Gemara questions Abaye's reasoning. According to Abaye, if a woman's husband dies without children and her brother-in-law is a Mukeh Shechin (a man afflicted with boils or leprosy), she should not be required to perform Yibum or even Chalitzah. She should be able to claim that "a'Da'ata d'Hachi Lo Kidshah" -- she did not marry her husband with the intent that if he dies she should have to marry the repulsive brother-in-law.
The Gemara answers that the case of the wife is different. In the case, it is clear that it is worthwhile for her to marry the first brother even with the risk that later she may have to do Yibum or Chalitzah with her repulsive brother-in-law. This is because a woman prefers to be married rather than to live alone.
The Gemara here seems to contradict the Yerushalmi. The Yerushalmi (Bava Metzia 7:7) states that when a man marries a woman and stipulates, "You are hereby married to me on condition that you will not do Yibum with my brother if I die childless," he is considered "Masneh Al Mah she'Kasuv ba'Torah" (making a condition against what is written in the Torah), and the marriage takes effect but the stipulation is null and void. How can the Yerushalmi be reconciled with the Gemara here, which assumes that if a woman marries with intent that she will not have to do Yibum with her repulsive brother-in-law, her condition is valid?
(a) The TERUMAS HA'DESHEN (end of 1:233) answers that the Yerushalmi and Bavli indeed disagree about this issue. According to the Bavli, one indeed may make a condition at the time of the marriage that Yibum will not be done with a certain brother.
The Terumas ha'Deshen writes in the name of "MORAM" that the Gemara here provides proof for the words of the GE'ONIM who ruled in a responsum that if the husband's brother was a Mumar (apostate) at the time of the wedding and the husband later dies, the widow does not have to do Yibum with the Mumar and may remarry even without Chalitzah. This is because it is clear that the bride married the man only on condition that she would not have to do Yibum with his brother who is a Mumar.
(b) The NODA B'YEHUDAH (EH 1:56, DH v'Al Devar) explains that the Yerushalmi and Bavli do not disagree. Rather, there is a distinction between stipulating that she will not fall to Yibum, and stipulating that if the need to do Yibum arises the original Kidushin will lose its validity. The former condition contradicts the Torah law that requires a woman to fall to Yibum. The latter condition, however, does not contradict the Torah. Rather, it is a condition in the original Kidushin which states that the Kidushin will not be valid in the event that the woman's husband dies childless.
(The REMA (EH 157:4) writes that when the husband has a brother who is a Mumar, he may make a double condition at the time of the marriage and say that if his wife later will have to do Yibum with the Mumar, his original Kidushin should be invalidated retroactively. The BI'UR HA'GRA (EH 157:13) writes that the source of this law is the Gemara here. The Noda b'Yehudah also writes that if he makes such a condition, it is possible that it takes effect.) (D. BLOOM)