We'll continue talking about the Shomrim (guardians) who swore falsely. We'll now talk about a Sho'el, somebody who is a borrower. A borrower would be obligated for any unavoidable loss, like an animal suddenly passing away. That is the responsibility of the borrower.
The Mishnah says, "A person says to a borrower, 'Where is the ox that I lent to you, that you borrowed from me?' The borrower said to him, 'It died.'" It died naturally. In that case, the borrower would still be responsible. But in reality, the ox was killed by a wild animal, captured by someone, stolen, or lost.
Or the borrower said, "It was killed by a wild animal," but it had died naturally, been captured, stolen, or lost. Or, as a third option, the borrower told him it was captured or stolen. But in reality, it had died naturally, been killed, been stolen, or been lost. Or the borrower said, "It was stolen," but in reality, it had died, been killed by wild animals, been captured, or been lost. The borrower said it was lost, but in reality, it had died naturally, been killed, been captured, or stolen.
So in all of these cases, the borrower would have been obligated anyway. Whatever claim he came with was a lie; the claim he made did not free him from anything. He was obligated no matter what. But then the person who gave him the animal to borrow told him, "I want you to swear; I'm putting you under oath about your claim." He answered, "I'm willing to swear." Even though the borrower here wasn't obligated to swear, he would have had to pay the lender no matter what. The lender pushed him to swear, and he went through with it. So we say that in this case, he lied. He didn't tell the truth about what happened to the ox.
But we still say patur. He's exempt from bringing the Korban Asham (guilt offering) and paying the extra fifth penalty. When the borrower is responsible for all unavoidable losses—like an animal dying naturally, being killed by wild animals, being stolen, being captured by someone, or getting lost—whatever the situation, he is responsible no matter what. So when he swore falsely that these things happened, he didn't do anything. He didn't get himself out of having to pay. He didn't exempt himself. Therefore, the oath didn't help him whatsoever. It didn't do anything. So he's not obligated to bring the Korban Asham or make that additional fifth payment.