The Gemara relates: A certain gentile mortgaged a house to Rav Mari bar Raḥel for a loan that Rav Mari had provided him. Afterward, the gentile sold the house to Rava. Rav Mari waited for twelve months of the year to pass, took the amount of money necessary to pay rent for the house and brought it to Rava, who was now the owner of the house. Rav Mari said to Rava: This fact that I did not bring the rental fee for the house to the Master until now is because an unspecified mortgage is in effect for a period of one year. If that gentile wanted to remove me from the house by paying back the loan, he could not remove me from it until now. Consequently, the house actually belonged to me for that year, and I was not required to pay rent. Now, since the gentile can remove me from the house by repaying the loan, the house belongs to you. Therefore, let the Master now take the rental fee for the house for the coming year.

Rava said to him: Had I known that this house was mortgaged to the Master, I would not have purchased it at all, as I would have given you the chance to purchase it first. Now, therefore, I will act toward you according to the law of the gentiles, as I assumed the rights previously held by the gentile. According to gentile law, as long as the borrower does not remove the lender by paying back the money, he also does not take a rental fee for the house, as there is no prohibition against a gentile paying or receiving interest. Therefore, I too will not take a rental fee for the house from you until I remove you by forcing the gentile to pay the money that is owed to you.

The Gemara relates: Rava of Barnish said to Rav Ashi: The Master sees the Sages who consume interest, as they give people money for wine in the month of Tishrei, and they select the wine later, in the month of Tevet. Had they taken the wine immediately upon payment, there is a chance that it would have spoiled. Now, in return for paying for the wine in advance, they receive the benefit of guaranteeing that the wine they receive will not be spoiled. Rava of Barnish understood that this benefit, received in exchange for advance payment, is a form of interest.

Rav Ashi said to him: They too gave the money at the outset for wine, but they did not give it for vinegar. That which was wine at the outset is still wine, and that which became vinegar was vinegar when they paid for it but they did not know it. It was at that time of selection that they merely selected the wine that they had paid for previously. Since they agreed to buy wine, not vinegar, the benefit of actually receiving wine does not constitute interest.

The Gemara relates: Ravina would give money in advance to the people of the fortress [akra] at the river Shanvata in order to buy wine to be supplied after the grape harvest, and when they supplied the wine they would pour an extra jug [kufita] of wine for him as a gift, although there was no stipulation between them requiring this. Ravina came before Rav Ashi to ask whether this involved interest. Ravina said to him: Is it permitted to do this? Rav Ashi said to him: Yes, it is permitted, as they forgo payment for the extra wine to your benefit in order to maintain good relations with you. Since the additional wine is not provided as consideration for the advance payment, there is no problem of interest.

Ravina said to him: But the land is not theirs. The people of the fortress at Shanvata worked land belonging to others who abandoned their fields because they could not pay the real estate taxes. The people of the fortress paid the taxes and were therefore able to use the fields. Ravina was concerned that perhaps they did not own the grapes and were therefore unable to forgo payment for the additional amount as it did not belong to them. Rav Ashi said to him: The land is liened to the king as payment for the taxes [letaska], and the king says: Whoever pays the tax may consume the produce of the land. Consequently, the ones who pay the taxes have ownership of the wine by dint of the law of the kingdom.

The Gemara relates that Rav Pappa said to Rava: Let the Master see these Sages who pay money for the tax [akarga] on behalf of other people and afterward make them work more than is reasonable for the amount of money they paid. Rava said to him: Now, if I were dead I could not say the explanation of this matter to you, so it is good that you asked me while I am still alive, as I know that this is what Rav Sheshet said: The document [moharkayyhu] of servitude of these people lies in the treasury of the king, i.e., all of his subjects are considered his servants, and the king said: The one who does not pay the head tax shall serve the one who does pay the head tax, and consequently, by dint of the law of the kingdom they can have them work as much as they want.

The Gemara relates: Rav Se’oram, the brother of Rava, would forcefully seize people who were not acting properly and have them carry Rava’s sedan chair. Rava said to him: You acted correctly, as we learn: If you see a Jew who does not behave properly, from where is it derived that you are permitted to have him work as a slave? The verse states: “Of them you may take your slaves forever; and over your brothers” (Leviticus 25:46). It is derived from the conjunctive “and” linking the two clauses of the verse that there are circumstances where it is permitted to treat a fellow Jew as if he were a slave. One might have thought that this is the halakha even if a Jew acts properly. To counter this, the verse states in the continuation: “And over your brothers the children of Israel you shall not rule, one over another, with rigor.”

Rav Ḥama said: With regard to one who gave money to another to purchase wine for him, and the other, i.e., the agent, was negligent and did not purchase it for him, the agent must pay the one who gave him the money according to the going rate of wine in the port city of Zolshefat, where the main wine market was located, and he must purchase the wine according to the price in that market even if it is more expensive than the amount he was given initially.

Ameimar said: I said this halakha before Rav Zevid of Neharde’a, and when he heard it he said: When Rav Ḥama said this, he said that statement in a case where the buyer asked the agent to purchase wine without specification concerning exactly which wine he wanted. But if he said to the agent: Buy this specific wine for me, the agent who neglected to buy the wine is not obligated to buy it at a higher price later, as when he was sent to buy it initially, who says that the owner would have sold it to him? The one who gave the money to the agent was aware of the fact that the agent may not be able to successfully purchase that specific wine. Consequently, the obligation of the agent is simply to return the money, and nothing may be added to that sum, due to the prohibition of interest.

Rav Ashi said: Even if he asked the agent to buy wine without specification, the agent is also not obligated to buy wine later for more than the amount he was given. What is the reason for this? The implicit obligation that the agent accepted upon himself, to pay the one who hired him with wine of a higher value than the amount of money he received, is a transaction with inconclusive consent [asmakhta], as any situation where one will have to pay more money than he received is similar to the payment of a fine, and the acceptance of an asmakhta does not effect acquisition, as his acceptance is assumed to be insincere.

The Gemara asks: And according to Rav Ashi, in what way is this case different from that which we learned in a mishna (104a) concerning a rental agreement for land, in which a sharecropper agreed to cultivate a field in return for a share of the produce and wrote: If I let the field lie fallow and do not cultivate it, I will pay with the best-quality produce? In that case, the sharecropper agreed to pay the amount he caused the owner to lose due to his lack of activity, and it was not ruled an asmakhta. The Gemara answers: There, the matter is in his power, as he can decide whether to work the field or not to work it.