Talmud - Kiddushin 28b קידושין כ״ח ב׳

once one party in the transaction acquires the item he is receiving, this party is obligated with regard to the item being exchanged for it. The novelty of the mishna is that all items, not only vessels, can be used to perform the act of acquisition of exchange. Therefore, one should not infer that the same is the halakha with regard to coins. The Gemara comments: The language of the mishna is also precise, as it teaches afterward: How so? If one exchanges an ox for a cow, or a donkey for an ox, once this party acquires the animal that he is receiving, this party is obligated with regard to the item being exchanged for it. This clause apparently explains the previous clause, and employs the example of animals, not coins. The Gemara summarizes: Learn from this clause that the mishna is referring to acquisition through the exchange of items, not money.

The Gemara asks: And with regard to what entered our minds initially, that a coin effects symbolic exchange, what is the meaning of the clause: How so, if one exchanged an ox for a cow, once this party acquires the animal that he is receiving, this party is obligated with regard to the item being exchanged for it. This example does not involve a coin. The Gemara explains that it was assumed that this is what the mishna is saying: Not only can a coin be used in the act of acquisition of exchange, but produce can also effect exchange. How so? If one exchanged meat of an ox for a cow, or the meat of a donkey for an ox, once this party acquires the item that he is receiving, this party is obligated with regard to the item being exchanged for it.

The Gemara asks: This works out well according to the opinion of Rav Sheshet, who says: Produce effects exchange, i.e., the mode of acquisition of exchange applies not only to vessels but also to produce and animals. But according to the opinion of Rav Naḥman, who says: Produce does not effect exchange, what can be said?

The Gemara answers: According to this opinion, the mishna is dealing with money alone, and this is what the mishna is saying: There is a transaction involving money that is like an exchange. How so? If one exchanged the monetary value of an ox for a cow, or the monetary value of a donkey for an ox, the transaction is effective. In this case, one sold his ox to another for an agreed sum of money, and after the buyer acquired the ox by pulling it, he then offered to give the seller his cow in exchange for the money that he owes him. In this case the cow is acquired without the seller having to pull it. Although this acquisition initially was to be an exchange, it is ultimately a purchase for money, as the second animal is acquired as a result of the forgiving of the monetary debt.

What is the reason for this ruling in light of the halakha that one cannot acquire movable property by means of money alone? The Gemara explains that Rav Naḥman holds in accordance with the opinion of Rabbi Yoḥanan, who said: By Torah law money effects acquisition, i.e., when one pays money he acquires the item, even if he has not yet performed another act of acquisition. And what is the reason that the Sages said that pulling acquires an item and money does not? This is a rabbinic decree lest the seller say to the buyer after receiving the money: Your wheat was burned in the loft. If a fire breaks out or some other mishap occurs after a seller receives the money, he will not bother to save the goods in his house because they no longer belong to him, and the buyer may incur a loss.

The Sages therefore decreed that acquisition takes effect only when a buyer pulls the item. The reason that the mishna allows a transaction that indicates that one can effect acquisition using only money is because that case of the mishna as explained by Rav Naḥman is an uncommon occurrence. It is rare for one who has sold his animal in exchange for money to change his mind and request an animal from the purchaser instead. With regard to a common occurrence, the Sages issued a decree, whereas in the case of an uncommon occurrence, the Sages did not issue a decree. Consequently, the Sages did not apply their decree to this situation.

The Gemara asks: And how is the mishna explained according to the opinion of Reish Lakish, who disagrees with Rabbi Yoḥanan and says that pulling is explicitly stated in the Torah? Reish Lakish maintains that the acquisition of movable property cannot be performed with money by Torah law, and therefore there can be no distinction between common and uncommon cases. This works out well if Reish Lakish holds in accordance with the opinion of Rav Sheshet, who says that produce effects exchange. If so, he can explain the mishna in accordance with the opinion of Rav Sheshet.

But if he holds in accordance with the opinion of Rav Naḥman, who says that produce does not effect exchange and a coin does not effect acquisition by Torah law or by rabbinic law, in what manner does he establish the mishna? The Gemara answers: Perforce Reish Lakish holds in accordance with the opinion of Rav Sheshet.

MISHNA: The authority of the Temple treasury effects acquisition by means of money to the seller. And the authority, i.e., the mode of acquisition, of a commoner [hedyot] is by possession. Furthermore, one’s declaration to the Most High, i.e., when one consecrates an item through speech, is equivalent to transferring an item to a common person, and the item is acquired by the Temple treasury through his mere speech.

GEMARA: The Sages taught in a baraita (Tosefta 1:6): How does the authority of the Temple treasury effect acquisition by means of money? With regard to the Temple treasurer who gives coins for an animal, even if the animal is at the other end of the world, he acquires it immediately. And with regard to a commoner, he does not acquire the animal until he pulls it.

How is one’s declaration to the Most High equivalent to transferring an item to a common person? With regard to one who says: This ox is a burnt-offering, or: This house is consecrated property, the Temple treasury acquires these even if they are at the other end of the world. There is no need for a further act of acquisition, as that statement alone is sufficient. Whereas with regard to a commoner, he does not acquire property in this manner

Traduction : The William Davidson digital edition of the Koren Noé Talmud, with commentary by Rabbi Adin Even-Israel Steinsaltz.

Kidushin 28b explores whether barter-based acquisition applies to animals and produce alone or extends to coins, debating Rav Sheshet and Rav Nachman's views.