1) THE DEGREE OF LIABILITY OF ONE WHO HOLDS AN OBJECT OF COLLATERAL
QUESTIONS: Rebbi Yitzchak states that a Malveh who takes collateral as security for a loan "acquires" it ("Ba'al Chov Koneh Mashkon"). RASHI (DH she'Koneh) writes that since the Malveh acquires the Mashkon, he is liable even for damages or destruction caused by Onsin.
The Rishonim have a number of difficulties with Rashi's opinion.
(a) TOSFOS and the RAMBAN challenge Rashi's opinion based on the fact that the Gemara here uses Rebbi Yitzchak's statement to explain the Mishnah (80b). The Mishnah states that the Malveh is considered only a Shomer Sachar for the Mashkon, and he is not liable in a case of Ones. Why, then, does Rashi say that the Malveh is liable if an Ones occurs?
(b) The RAMBAN quotes the Gemara in Bava Kama (36b) which states that if an ox (Shor Tam) causes damage and the victim seizes the ox as collateral for compensation, his liability for the ox is that of a Shomer Sachar. In that case, the Mashkon is seized after the time of the damage, when the Mazik has already incurred a debt (similar to the case of the Gemara here), and yet the Gemara there says the holder of the Mashkon has the liability of a Shomer Sachar and not the liability of a Sho'el. Why, then, does Rashi say that he is like a Sho'el?
ANSWERS: The SHACH (CM 72:9) points out that the wording of Rebbi Yitzchak's statement itself, "Ba'al Chov Koneh Mashkon," supports the view of Rashi. Since it is a Kinyan, it follows that all of the responsibility for the object rests upon him. The Shach offers the following answers to the Rishonim's questions on Rashi.
(a) The Shach answers that when Rashi says that the Malveh is liable for any Ones that occurs, this refers only to when the Mashkon was taken after the loan was given. In contrast, the Mishnah (80b) refers to a case in which the Mashkon was taken at the time of the loan, in which case even Rashi agrees that the Malveh has only the liability of a Shomer Sachar. The Gemara later says that Rebbi Yitzchak's statement refers only to a Mashkon that was taken after the time of the loan, in which case the Malveh is liable for Onsin. Rebbi Yitzchak's statement does not apply to a Mashkon taken at the time of the loan, and thus there is no source that indicates that the Malveh would be liable for an Ones that happens to such a Mashkon.
(b) The Shach answers that the Gemara in Bava Kama refers to a case in which the Mashkon that was seized was an ox, a Shor Tam. The owner of a Shor Tam is not obligated to pay for damages caused by his Shor Tam until Beis Din issues a verdict that he must pay. Hence, at the moment that the Nizak seized the Shor Tam, the Mazik was not yet obligated to pay for damages, even though the Shor Tam had already caused damage, since Beis Din had not yet issued a verdict obligating him to pay. When Rashi says that a Malveh acquires the Mashkon completely and is liable for Onsin, he refers only to a case in which the Malveh obtained the Mashkon as a payment for the loan. In the case of the Shor Tam in Bava Kama, though, the debt did not yet exist when the ox was seized, and thus it is obvious that the Mashkon cannot be considered payment for the debt. The Shor Tam is merely a Pikadon. It is similar to an item that a craftsman worked on and which he retains merely in order to ensure that he will be paid for his work. In such a case as well, the craftsman is considered a Shomer Sachar. (Y. MARCUS)
2) HALACHAH: ONE WHO IS INVOLVED IN A MITZVAH IS EXEMPT FROM OTHER MITZVOS
QUESTION: RASHI (DH v'Hacha b'Shomer) explains that one who is watching an Aveidah is exempt from giving Tzedakah because of the principle of "ha'Osek ba'Mitzvah Patur Min ha'Mitzvah" -- "One who is involved in one Mitzvah is exempt from another Mitzvah." Hence, in the case of the Gemara, the person who is involved in the Mitzvah of Hashavas Aveidah is exempt from the Mitzvah of Tzedakah.
If one is exempt from a Mitzvah while he is involved in the performance of another Mitzvah, then every man who wears Tzitzis or Tefilin should be exempt from all other Mitzvos! This certainly is not the Halachah, though. When exactly does involvement in one Mitzvah exempt a person from another Mitzvah? (TOSFOS Sukah 25a, DH Sheluchei Mitzvah)
(a) TOSFOS in Sukah answers that only when the second Mitzvah will interrupt one's performance of the first Mitzvah is one exempt from the second Mitzvah. If the fulfillment of the second Mitzvah will not interfere with one's performance of the first Mitzvah (such as in the case of the Mitzvah of Tzitzis or Tefilin), he is not exempt from the second Mitzvah.
The OR ZARU'A questions the answer of Tosfos. It is obvious that one may not interrupt one Mitzvah in order to perform another. Why would one have thought that one Mitzvah takes precedence over another, had the verse not taught otherwise?
Perhaps Tosfos learns from the verse that one who is involved in one Mitzvah is exempt from other Mitzvos even in a case where the opportunity for the second Mitzvah will pass if it is not done right away. One might have thought that in such a situation, he should interrupt the performance of the first Mitzvah and fulfill the second Mitzvah. The verse teaches that even in such a case, one may not interrupt the first Mitzvah to perform the second. (M. KORNFELD)
(b) The RASHBA in the name of RAV HAI GA'ON, the MAGID MISHNEH (Hilchos Sukah 6:4) in the name of the GE'ONIM, and the OR ZARU'A (Hilchos Sukah) explain that as long as a person is involved in the preparations for a Mitzvah, such as one who is traveling in order to perform a Mitzvah, he is not obligated by the Torah to perform other Mitzvos even if they do not distract him from the first Mitzvah. Hash-m does not expect a person to do two things at once.
Accordingly, with regard to Tzitzis and Tefilin, one has already done all that was necessary in order to prepare for the Mitzvah. The man who wears Tzitzis or Tefilin is now in the process of passively fulfilling the Mitzvah and not in the process of preparing to fulfill the Mitzvah. The exemption from other Mitzvos applies only when one has not yet fulfilled the first Mitzvah and is involved in the preparatory stages of fulfilling the Mitzvah.
(c) The RAN (Sukah 25a) suggests a compromise. He agrees with the Rashba that one is exempt from the second Mitzvah even if its performance does not distract him from the first Mitzvah. However, if there is a way for him to fulfill the second Mitzvah and still perform the first Mitzvah in its normal manner, then he is not exempt from the second Mitzvah (as the Ran writes, "why not fulfill a Mitzvah if nothing is lost while doing so?"). Only when he must change the normal way in which he performs the first Mitzvah in order to fulfill the second Mitzvah is he exempt from the second Mitzvah.
(According to the Ran, it is possible that the obligation to do the second Mitzvah does not stem from the normal obligation to perform Mitzvos, but rather from the requirement that one avoid disgracing a Mitzvah. Technically, he may be exempt since he is involved in another Mitzvah, but in practice -- since he could perform the second Mitzvah without any deviation from his normal way of performing the first Mitzvah -- he must perform the second Mitzvah in order not to disgrace it. -M. KORNFELD)
HALACHAH: The REMA (OC 38:8) cites the opinion of the Ran as the Halachah. When there is a way to fulfill the second Mitzvah and still perform the first Mitzvah in its normal manner, he is not exempt from the second Mitzvah. If there is no way to fulfill the second Mitzvah and perform the first Mitzvah in its normal way, he is exempt from the second Mitzvah. (See also Insights to Berachos 11:1 and Sukah 25:2.)