We learned two different things in the last perek (chapter). As we said in the last Mishnah, a borrower would be responsible for any damage or loss that happens to the item he is borrowing. Even if it was an accident, and even if it had nothing to do with him—he couldn't have prevented the problem. Number one, that's a borrower. Number two, we also learned that a socher (renter) would not be responsible for an accidental loss that he did not have the ability to prevent.
So in this Mishnah, we'll talk about a situation where somebody had both of these statuses. He was a renter and a borrower, and the animal he was using died accidentally. So the question is: Is the person in question considered to be a borrower, and is the animal a borrowed animal, so he would be responsible? Or is he a renter who rented the animal, and therefore would not be responsible?
How could you have a case where a man is both a borrower and a renter? First, we'll spell out three scenarios where he could be both, and then we'll get into the din (law). Somebody borrows a cow. First possibility. The second possible scenario is that he borrows it for half a day and rents it for the other half of the day. Number two: he borrows it for today and rents it for tomorrow. Or he rents one cow from the owner and borrows another cow from him. And the cow dies.
The problem is, you don't know when it died. You don't know if it died during the time that the cow was borrowed, or during the time that it was rented. Either he didn't know at what part of the day it died, or, in the scenario where he borrowed it for one day and rented it for the next day, you don't know on which day it died. In the third scenario, you don't know which cow died. You don't know if it was the borrowed cow that died or the rented cow that died.
So therefore, you have all these sfeikot (doubts). What is the responsibility of this person, who was a renter and a borrower? The Mishnah continues. There are a few different types of claims that the owner and the borrower/renter could have made, so we have to lay the groundwork for all of them. There are no witnesses to say when this animal actually died. So we'll go through all the possible claims of the borrower and lender and see how the halacha (Jewish law) is different in each one of them.
Let's talk about the first one. The Mishnah says that the owner of this cow, the lender here, is saying that the borrowed cow is the one that definitely died, in the scenario where there are two different cows. Or, in the scenario where it was borrowed for one day and rented for the next day, the owner says it definitely died on the day that it was borrowed. The owner wants the borrower to be the one who is responsible and has to pay, as opposed to that borrower being a renter. Or, in the third scenario, the owner is claiming that it died during the half of the day that it was borrowed, and not during the half day that it was rented. So he's saying it definitely was borrowed at that time. Again, the person is a borrower, and he is responsible. The other person, the borrower and possible renter, says, "I don't know when it happened." And therefore, what happens in this case? Chayav: the borrower is obligated to pay for the cow. The borrower would have to take an oath that it didn't happen during the time that he was borrowing it, but rather that it happened during the time that he rented it. He can't take that oath because he doesn't know. He's admitting to us that he doesn't know. And therefore, he's required to pay.
The Gemara has a very lengthy and in-depth discussion about what's really going on here. Even though we hold by the klal (principle) of bari v'shema—if someone's making a definite claim and someone's making a possible claim—bari adif (we accept the definite claim). There's another klal that goes against that. Another klal says, bari v'shema, lav bari adif. If you have a definite claim and a possible claim, we don't say that the definite claim is taken as the correct one, because there's no proof here. So the Gemara has to work out how we end up saying that the person is chayav, that the borrower here would be obligated to pay for the cow, if we don't hold by that klal. That's the first possible set of claims they could have.
Number two: the renter here is making a definite claim. He's saying, "It's definitely the rented cow, as opposed to the borrowed cow, that died. So I'm not responsible, because it was a rented cow that died." And we know a socher is not responsible for situations where it was just an accident, nothing he could have done to prevent it. Or he makes a claim that, in the scenario where the cow was rented for one day and borrowed for another day, it died on the day that it was rented. So the socher is claiming that he's not responsible as well. Or, in the third case, when it was borrowed for half a day and rented for half a day, it died during the time that it was rented. "So I'm also not responsible here." In all of these cases, the owner of the cow says, "I don't know. I don't know when it died. I don't know what happened here, so I can't really give an opinion."
We say patur: the renter here is exempt from paying for the cow, because there's no obligation for the renter to take an oath in this situation. He's telling you when it happened, and the owner doesn't have a definite claim against him. You can only force him to swear when there's a definite claim. If the owner of the cow says, "No, it died when the cow was being borrowed," there's no claim against him. So therefore, we can't force him to swear, and he would be exempt from paying. Somebody trying to extract money from a friend really has to bring clear proof.
Third possible set of claims. Now you have two opposing claims. The owner of the cow is claiming that the cow was definitely borrowed at the time that it died. If it was borrowed, it would be the sho'el (borrower) who would be responsible. It would be the person who was using the cow at the time. But the renter is saying, Zeh omer sechurah: the renter is saying, "No, the cow was rented at the time. It wasn't borrowed. And therefore, I'm not responsible." He's claiming that because it was rented, he was paying a fee, and he wouldn't be responsible in that scenario.
We say the renter should take an oath that the cow was rented when it died, and then he wouldn't have to pay. Since he's very sure about the scenario, he claims he knows when it died, so there should be nothing holding him back from swearing that his claim is true. If he swears, he would not be obligated to pay.
And the last scenario: Zeh omer eini yodea. The owner of the cow says, "I don't know when it died." The one who was borrowing/renting it says, "I also don't know when it died." They both say they don't know if the cow was being rented by the person or being borrowed by the person. They don't know when it actually died. We say they divide the loss of the cow. The borrower pays for half of the value, and the owner loses half of the value.