Introduction. A person that rents a cow, and the cow dies naturally, takes an oath that it died naturally and does not have to pay for it because it was not his fault. But a person that borrows a cow and it dies naturally has to pay. In the language of the Gemara this is שומר חינם נשבע על הכל. שואל משלם על הכל. שומר שכר נשבע על אונסים גדולים כמו לסטיים מזויימים ומשלם על אונסים קטנים כמו גניבה ואבידה and we are saying a renter is like a paid guard.
I am sorry not to have written anything about the Gemara for a long time but my head has been in mathematics for a while. but today I just wanted to share one thought about Adi bar Abin's statement and Abyee's answer in Bava Metzia page 35. There the Sages say if you have a renter who rents a cow and loans it to a borrower. Then the cow died naturally. The Sages said the renter takes an oath and the borrower pays him [not the owner]. Adi bar Abin objected to this '' let the owner tell him 'I do not need you nor your oath'. Abyee answered '' the sages are saying that the renter gets possession not at the time of the oath but the time of the death of the cow.
It occurred to me to wonder about what abyee means. I thought perhaps he means like the opinion in the Gemara that a guard of an object has a sort of possession in the object, but then i thought that can't be what Abyee means since then he would have said the possession starts right when it is given over to guard. So I think you have to say like Reb Aaron Kotler that he means the prior assumption is with the renter even before he takes the oath. it is after all natural for a cow to die. the only reason for the oath is to appease the owner. but even without that the assumption is that he should not have to pay.
