1) THE BLESSING FOR THE MITZVAH OF "PIDYON PETER CHAMOR"
QUESTION: The Gemara concludes that one may redeem a Peter Chamor with a lamb that is worth a "Rigya," or an average sum of money. TOSFOS (DH Hilchesa) discusses the Halachos of Pidyon Peter Chamor, and he writes that when the owner redeems his firstborn donkey he must recite the blessing, "Al Pidyon Chamor." He does not recite the blessing when he gives the lamb to the Kohen, because from the moment that he designates the lamb it is already considered to be in the property of the Kohen. This is the Halachah as cited by the SHULCHAN ARUCH (YD 321:6).
Although one does not recite a blessing when he gives the lamb to the Kohen, why -- at the time that he performs the Pidyon -- does he not mention the Mitzvah to give the lamb to the Kohen, if he is performing that Mitzvah as well at that moment, as Tosfos says? He should say a blessing (or blessings) for both fulfilling the Mitzvah to redeem the firstborn donkey and for fulfilling the Mitzvah to give the lamb to the Kohen!
(a) The PERISHAH (YD 321:15) answers that a blessing is recited only when the act of the Mitzvah permits something to its owner. When a person performs the Mitzvah of Pidyon Peter Chamor, the donkey's Kedushah is removed and it becomes permitted to its owner. The giving of the lamb to the Kohen in place of the donkey does not permit anything to the donkey's owner.
Similarly, when one performs the Mitzvah of giving the firstborn of a Kosher animal to the Kohen, he recites no blessing, because the fulfillment of the Mitzvah of giving the Bechor to the Kohen does not permit anything to the owner.
(b) The TAZ (YD 321:7) does not accept the Perishah's answer. The fact that the giving of the Bechor of a Kosher animal permits nothing to the owner does not diminish the Mitzvah in any way, and a blessing should be recited. The Taz suggests instead that a blessing is recited only when one performs a Mitzvah with his own property. The firstborn of a Kosher animal belongs to the Kohen from the moment that it is born. Similarly, the lamb belongs to the Kohen from the moment that it is designated in place of the donkey. The owner is merely giving to the Kohen what already belongs to him. Since the giving of the animal to the Kohen is not a Mitzvah that one does with his own property, he recites no blessing for that Mitzvah.
This is also the approach of the TESHUVOS HA'MEYUCHASOS L'RAMBAN (#189), as cited by the YOSEF DA'AS (12b).
(c) The words of Tosfos imply that there is no actual Mitzvah to give to a Kohen the lamb of Pidyon Peter Chamor, or the Bechor of a Kosher animal. The Mitzvah is that the lamb, or Bechor, is Kadosh and becomes the Kohen's property. It is not a Mitzvah that obligates the person to do a certain act, but rather it is a Mitzvah that describes the status of a specific object or situation, similar to the laws of purchase that describe which acts cause a transfer of ownership without obligating a person to perform a specific act. (See SEFER HA'CHINUCH #18 and #336.)
Accordingly, the reason why the animal must be given to a Kohen is that it his property, and withholding it from the Kohen constitutes theft. It is only the Isur against stealing that obligates the owner to give the animal to the Kohen. No blessing is recited for a Mitzvah that merely describes the status of an object.
2) HOW MANY LAMBS ARE NECESSARY TO REDEEM TEN DONKEYS
QUESTION: Rav Nachman in the name of Rabah bar Avuha discusses a case in which a Yisrael inherited ten firstborn donkeys from his mother's father, a Kohen, who had inherited them from his own mother's father, a Yisrael. Since the donkeys were in the possession of a Yisrael when they were born, the obligation to redeem them took effect. The Kohen who inherited them was required to redeem them, but, being a Kohen himself, he had no obligation to give the lambs to a Kohen. Since he did not redeem them himself, his grandson who inherited them must redeem them. He may keep the lambs for himself, since his grandfather, the Kohen, would have kept the lambs for himself. However, when he separates ten lambs as Pidyon for the ten donkeys, he must separate Ma'aser Behemah from the lambs, as he must do with any ordinary sheep.
Why, though, must he use ten lambs to redeem the ten firstborn donkeys? The Mishnah (9a) explicitly states that a lamb used to redeem a firstborn donkey "may be re-used to redeem many firstborn donkeys"! As long as the lamb remains the Yisrael's possession, he may re-use it for as many acts of Pidyon as he wants. (TOSFOS DH she'Hayu)
(a) TOSFOS suggests that, indeed, it suffices to use one lamb to redeem all ten firstborn donkeys. The reason why the Gemara mentions a case in which ten lambs are used is that it wants to teach that Ma'aser Behemah applies even to a flock that is comprised entirely of lambs used to redeem firstborn donkeys.
(b) The RAMBAM (in Perush ha'Mishnayos) reads the Mishnah differently. According to his reading, the Mishnah makes no mention of using one lamb to redeem multiple firstborn donkeys. Instead, the Mishnah reads, "Ba'al Mum, Podeh Bo. Pe'amim Harbeh Nichnas l'Dir l'His'aser" -- "a Ba'al Mum may be used to redeem a firstborn donkey. It frequently occurs that lambs that were used to redeem doubtful firstborn donkeys are gathered in order to separate Ma'aser Behemah from them." (That is, when one has ten lambs that were used to redeem ten firstborn donkeys, he must separate one of them as Ma'aser.) According to this reading, the ruling of Rav Nachman in the name of Rabah bar Avuha here is the same law that the Mishnah teaches.
When he records the Halachah, the Rambam, consistent with his reading of the Mishnah, does not write that one lamb may be used to redeem more than one firstborn donkey. (See BEIS YOSEF YD 321.)
However, the Rambam's reading is difficult to reconcile with the Gemara earlier (4b) which clearly reads the Mishnah as Tosfos does ("Podeh Bo Pe'amim Harbeh") and infers that one lamb may be used to redeem many firstborn donkeys. Perhaps the Rambam understood that the Amora'im disagree on the interpretation of the Mishnah, and he chose to rule in accordance with the Gemara here, which requires ten lambs for the redemption of ten firstborn donkeys.
3) REDEEMING A "PETER CHAMOR" WITH MONEY
QUESTION: Reish Lakish states that when one does not have a lamb with which to redeem his firstborn donkey, he may redeem it with money or any other object that is equal in value to the donkey. The Gemara explains the logic for this. The law of Pidyon Peter Chamor cannot be more stringent than the law of Hekdesh, which may be redeemed with money. A lamb is unique only in that it may be used for Pidyon even when it is worth less than the value of the donkey.
The TUREI EVEN in Megilah (23b, cited by the GILYON HA'SHAS) asks that when one redeems Hekdesh, the Pidyon takes effect even when one uses money that is less than the value of the item of Hekdesh. If, as the Gemara here asserts, the law of Pidyon Peter Chamor cannot be more stringent than the law of Hekdesh, then why does Pidyon Peter Chamor require that money in the exact value of the donkey be used for Pidyon?
ANSWER: The DEVAR AVRAHAM (quoted in SHEMEN ROKE'ACH) answers that the reason why one may redeem Hekdesh with less than its full value is the rule, "Ein Ona'ah l'Hekdesh" -- the laws of Ona'ah do not apply to Hekdesh. When one overcharges (or underpays) Hekdesh, he is not required to return the value that Hekdesh lost. In this respect, Hekdesh indeed is "less stringent" than Chulin. The Torah explicitly teaches that Hekdesh is less stringent in this respect. Moreover, this is a monetary law, and not a law related to Isur v'Heter, and thus it is not illogical that Hekdesh should be less stringent.
Accordingly, the laws of Pidyon for Peter Chamor can be more stringent than Pidyon for Hekdesh, since the law of Ona'ah does apply to Peter Chamor.
4) A LAMB THAT DIED BEFORE IT REACHED THE KOHEN
QUESTION: The Mishnah (9a) states that if the lamb designated as Pidyon for a firstborn donkey died, one is permitted to derive benefit from its corpse.
The Gemara asks that the Mishnah cannot be discussing a case in which the lamb died after it reached the Kohen, and when the Mishnah says that one is permitted to derive benefit from it, it means that the Kohen may derive benefit from it, because that is obvious. The Kohen certainly may derive benefit from his own property! It must be that the Mishnah is discussing a case in which the lamb died before the Yisrael gave it to a Kohen. The Mishnah is teaching that the Kohen may derive benefit from the lamb, even though it has not yet physically entered his domain. Since the lamb becomes the property of the Kohen at the moment it is designated as Pidyon for the donkey, the Kohen may derive benefit from it.
However, this, too, seems obvious. If the firstborn donkey itself becomes permitted to the Yisrael at the moment that the lamb is designated as its Pidyon, then it is obvious that the lamb becomes the property of the Kohen at that moment as well! The Mishnah cannot be teaching that the Yisrael may benefit from the Peter Chamor at the moment that he designates the lamb as Pidyon, because a different Mishnah (12b) teaches this. Why, then, is it necessary for the Mishnah to teach that the lamb belongs to the Kohen even before it is given to him?
(One cannot answer that the Mishnah (9a) is teaching that the Halachah follows the Chachamim (12b) and not Rebbi Eliezer, who maintains that the Pidyon does not take effect until the Kohen receives the lamb, because the Mishnah would be a "Stam Mishnah" following the view of the Chachamim, followed by a dispute in the next Mishnah (12b). In such a case (an anonymous Mishnah followed by a dispute), the Halachah does not follow the anonymous Mishnah (Yevamos 42b), and the Halachah would follow the view of Rebbi Eliezer.)
ANSWER: The MAHARIT ALGAZI answers based on the words of the SHITAH MEKUBETZES (4b, #4, in the name of the TOSFOS CHITZONIYOS). The Shitah Mekubetzes explains that when the Mishnah (9a) says that if the Kohen returns the lamb to the Yisrael, then the Yisrael may redeem additional firstborn donkeys with it, it is teaching that the lamb does not acquire the Kedushah of Peter Chamor, and, therefore, it may be used to redeem additional donkeys. When the Mishnah continues and says that if the lamb died, then one may benefit from it, it is teaching that the lamb does not acquire the same Kedushah as the Peter Chamor. Even though one may use the lamb to redeem additional donkeys, one might have thought that as long as the lamb belongs to the Yisrael, it possesses Kedushah and one may not derive benefit from it until it reaches the Kohen, at which point it loses its Kedushah.
(The Gemara later (32a) teaches a similar Halachah. When one designates an object as "Cherem" which must be given to a Kohen, as long as it is still in the property of the Yisrael it is Hekdesh, but once it is given to the Kohen it loses its Kedushah and becomes Chulin.)
Therefore, it is necessary for the Mishnah to state that even though the lamb died while in the possession of the Yisrael, one is permitted to derive benefit from it; it does not become permitted only when it reaches the Kohen (unlike the law of "Cherem"). (D. BLOOM)