1) THE LIABILITY OF A "SHULCHANI"
QUESTION: The Mishnah states that when a person leaves money with a Shulchani that is not wrapped and sealed, the Shulchani has permission to use the money. Therefore, if the money is lost, the Shulchani is obligated to compensate the owner, even if the Shulchani had not yet used the money.
In the Gemara, Rav Nachman says that until the Shulchani uses the money, he has only the status of a Shomer Sachar, who is Chayav for Geneivah v'Aveidah. If an Ones happens to the money, though, the Shulchani is exempt, because he is not considered a Sho'el (who is Chayav for Onsin) until he actually uses the money. Rava asks that if the Shulchani is not considered a Sho'el because he has not yet had any benefit from the money, then why is he considered a Shomer Sachar? What "Sachar," or benefit, has the Shulchani received from the money?
Rav Nachman answers that the Shulchani has indeed received benefit from the money, since he is permitted to use it if the opportunity to make a profit arises. The potential ability to use the money is enough of a benefit to make him a Shomer Sachar.
How does this explain why the Shulchani is not a Sho'el? Once he has permission to use the money, he should have the obligations of a Sho'el regardless of whether or not he uses the money, just as anyone who borrows an object is Chayav for Onsin right away, even before he uses the object.
ANSWERS:
(a) The S'MA (CM 292:16) writes, based on the RA'AVAD, that this form of "usage" -- the right to use the money if an opportunity to profit arises -- is an inferior form of usage, because the Shulchani will be reluctant to use the money in case the owner suddenly comes and demands his deposit back. Therefore, before the Shulchani actually uses the money, he is not considered a Sho'el because a normal Sho'el is not reluctant to use the object that he borrowed, while the Shulchani is reluctant to use the money entrusted to him.
(b) The LEVUSH YESHA answers that in a normal case, a Sho'el borrows an object completely for his own benefit. Here, though, the Shulchani has received the money from its owner in order to do a service -- to guard the money -- for the owner. Therefore, even though the Shulchani has the right to use the money, he is not yet considered a Sho'el since the money was not given to him exclusively for his own benefit. (I. Alsheich)

43b----------------------------------------43b

2) "HA'CHOSHEV LI'SHLO'ACH YAD"
OPINIONS: Beis Shamai and Beis Hillel disagree about the law in the case of a Shomer who "thinks" about using a Pikadon for his personal use without permission of the owner, but who has not yet actually used it. Beis Shamai says that the Shomer is considered as though he was "Shole'ach Yad" and he has the status of a Ganav, even though he has not actually used the object but merely "thought" about using it.
Does Beis Shamai literally require only that the Shomer think about using the object, or must the Shomer do more than just think about using the object in order to become Chayav?
(a) TOSFOS, the RAMBAN, and the RITVA understand that it does not suffice for the Shomer merely to think about being "Shole'ach Yad," but rather he must verbally state his intentions in order to be Chayav. (This also seems to be the view of RASHI here. The BACH, however, points out that Rashi in Kidushin explains otherwise. See (b) below.)
Why, then, does Beis Shamai describe the case as one in which the Shomer "thinks" about being "Shole'ach Yad"? The Ramban explains that when a person says that he is going to do an action but has not yet actually done it, he is called one who "thinks" of doing that action.
The Ritva explains that Beis Shamai uses this terminology because the Shomer does not have to verbalize his intentions specifically in front of witnesses in order to be Chayav. (Why, then, does Rashi here write specifically that he verbalizes his intentions "in front of witnesses"? The GILYONEI HA'SHAS answers that Rashi adds this only for a practical reason. Since the Mishnah implies that Beis Din makes the Shomer liable, they need proof to make him liable. The witnesses serve as proof of what the Shomer said. Alternatively, the NEFESH CHAYAH writes that the Chiyuv of Shelichus Yad engendered by the Shomer's speech is -- according to Rashi -- a Chiyuv of Kenas, penalty, because no real action was done. In order to become Chayav for a Kenas, there must be witnesses.)
(b) RASHI in Kidushin (42b, DH l'Chayev Al ha'Machshavah) writes that if the Shomer "said or thought" to be "Shole'ach Yad," he is Chayav. This is also the view of the ROSH (in Hilchos Ketanos, Hilchos Sefer Torah 3) in the name of RABEINU BARUCH.
The Ramban explains, according to this opinion, that even though the verse says, "Al Kol Devar Pesha" (Shemos 22:8), implying that one is Chayav only when he uses speech to express his intentions, thought and speech are considered identical as long as no action has been done. (I. Alsheich)