How do we know that a person can make another take an oath by extension even if he is not certain about that he owes him money? The answer is by comparison with the sotah oaths. The sotah oath is by its very nature a case of uncertainty. We do not know if the woman committed adultery or not. Nevertheless, she can be forced to take an oath and an oath by extension. So too in cases that occur outside the Temple—one can force another to take an oath by extension even in cases of uncertainty.
The sugya continues to discuss loan extensions, asking their limits. If person A can make person B take an oath about a financial matter, can he make him take an oath about anything else?
The institution of oath extension goes as far as one wants to take it. He can even make him take an oath that he owns him—swear that you are not my slave.
The problem is that one who gratuitously calls another person a name such as “slave” or “mamzer” is punished (by being excommunicated, by being lashed, or by losing his livelihood). How then could we let someone call another person that in a court of law?
Rava adjusts the resolution slightly—he must swear that he was not sold as a Hebrew slave. Being a Hebrew slave is not so ignominious because it does not affect one’s language.
The problem with this is that saying that someone else is your Hebrew slave is essentially saying that he owes you money. A Hebrew slave is like an indentured servant. This is not a good example, therefore, of an oath being overextended. It is a simple extension of an oath from one issue of money to another.
The Talmud resolves by saying that to Rava this is not simply a monetary claim. To Rava, the master owns the Hebrew slave and therefore this is a further extension of the oath.
If the slave is owned by the master, then this is the same as land and we have already learned that if one can impose an oath on another over movable property, he can extend it to land. So what new halakhah are we learning here?
The answer is that were it not for this statement, I would have thought that oath extensions work for land, because people sell land secretly. The purpose of the oath is to uncover the truth, truth that would not have been otherwise unknown. So one might need to make the other take an oath over land. But if a person sells himself into slavery, everyone would know that he had done so. Therefore, we would not need to make him take an oath over such a matter. This is why the Talmud says oath extensions can even go this far. Even though it seems very unlikely that B is actually A’s Hebrew slave (had this been true we would know of it), A can still make him take an oath that he is not.
This mishnah discusses acquiring things through barter.
The general rule of acquiring things through exchange is illustrated simply in the example of the cow and ox. If Reuven and Shimon exchange an ox for a cow, when Reuven takes physical possession of Shimon’s cow, Shimon becomes owner of the ox, even if Shimon doesn’t take physical possession. The implication would be that if the ox dies or is stolen, Shimon is out of luck for it is his ox that died or was stolen. Alternatively, if the oxen market rises dramatically Shimon wins out. For better or for worse, in an exchange once one party takes possession of one of the objects being exchanged, the other party automatically owns the other object.
Today’s section discusses exchanges by barter. What types of exchanges are considered irreversible? Particularly, can coins and produce be used as barter?
The Talmud asks what this item is that is being exchanged for another item. If that item is money, then barter can be performed with money. This would mean that if I give you money for your cow, then I have acquired your cow and neither of us can renege. The problem with this is that we have learned that money cannot be used to acquire objects.
Rav Judah explains the mishnah—for an item to be used as barter it must be something that does not have a value that can be expressed in its own terms. For instance, I could say a Hershey Bar is worth four Hershey kisses or two Goldenberg’s chews (I really loved those). But I cannot say how much a Hershey bar is worth in terms of Hershey bars. But a coin’s value is expressed on its own terms—a dollar is worth a dollar. Therefore, coins cannot be used in barter.