2,686. A Thief and an Oath of Deposit

Hilchos Shevuos 8:8

One is liable for a for an oath of deposit when he stole another person’s ox, as follows: person A accuses person B of the theft and demands payment. Person B denies stealing it and person A replies, “Oh, yeah? Then why is it in your possession?” Person B replies that person A asked him to watch it, and B supports his claim with an oath. The reason he’s liable is because if he had admitted to stealing it, he would have been obligated to pay; by claiming that it was entrusted to him, he exempts himself from paying for theft and for loss.

Hilchos Shevuos 8:9

Similarly, if person B claimed that he rented the ox and supported his claim with an oath, he would be liable for an oath of deposit. This is because he absolves himself for responsibility in cases of injury or death. Similarly, if he claimed to have borrowed the ox and supported his claim with an oath, he would be liable for an oath of deposit because doing so absolves him of responsibility in a case where the ox dies while doing its work. This will be explained IY”H in Hilchos Sh'eila U’fikadon.