The Gemara asks: You may become a guarantor for whom? If we say it means a guarantor for a Jew who lends money to another Jew with interest, that is difficult. But this would be contradicted by that which the Sages taught in a mishna (75b): These are the ones who transgress a prohibition: The lender and the borrower, the guarantor and the witnesses. It is prohibited to serve as a guarantor for such a loan.

Rather, it must mean that one may serve as a guarantor for a gentile who lends to another Jew with interest. This is also difficult, since the law of the gentiles is that he goes after the guarantor to collect the money without trying to collect first from the borrower. Under gentile law, it is the responsibility of the guarantor to pay the lender and to then retrieve the money from the borrower. Consequently, when this occurs, the guarantor is considered to have borrowed money from the gentile and lent it himself to the Jew, with the result that the guarantor is the one who takes the interest from the borrower, which is prohibited.

Rav Sheshet said: The case is that the gentile accepted upon himself to have this transaction judged by the laws of the Jews, so that he may not claim repayment from the guarantor. The Gemara asks: If the gentile accepted upon himself to have this transaction judged by the laws of the Jews, he should also not take interest, since that is prohibited by Jewish law. In response, Rav Sheshet said: He accepted upon himself the laws of the Jews with regard to this, the procedural matter with regard to the method of collection, but he did not accept upon himself the laws of the Jews with regard to that, the prohibition against taking interest.

§ The mishna teaches: A Jew may serve as a middleman and lend a gentile’s money to another Jew with the knowledge of the gentile, but not with the knowledge of a Jew, i.e., the middleman himself. The Sages taught in a baraita: A Jew may lend a gentile’s money as a middleman to another Jew with the knowledge of the gentile, but not with the knowledge of a Jew. How so? In the case of a Jew who borrowed money with interest from a gentile and then wanted to return it to him, but at that point another Jew found the borrower and said to him: Since you do not need this money anymore and I do need it, give it to me and I will pay you with the addition of interest in the same way that you pay the gentile, this is prohibited, since this is interest paid to a Jew. But if the borrower presented the second Jew to the gentile and the gentile agreed to this arrangement, it is permitted.

The baraita continues: And similarly, if a gentile borrowed money with interest from a Jew and then wanted to return it to him, and another Jew found the gentile and said to him: Give it to me and I will pay you interest in the same way that you pay the Jewish lender, this is permitted, since he pays interest to a gentile and not to a Jew. But if the gentile borrower presented the second Jew to the Jew who lent him the money and the Jewish lender agreed to this arrangement, it is prohibited.

The Gemara discusses the baraita: Granted, the latter clause of the baraita, which says that it is prohibited for a Jew to pay the gentile borrower when the Jewish lender is aware of the transaction, can be explained as a stringency due to concern about the prohibition of interest, but in the first clause the Jewish lender presents the Jewish borrower to the gentile before handing him the money, and the fact that this is permitted indicates that he acts as the gentile’s agent, not on his own. But since the halakha is that there is no agency for a gentile, this means that the Jew is the one who takes the interest from the second borrower. Why, then, does the baraita permit it?

Rav Huna bar Manoaḥ said in the name of Rav Aḥa, son of Rav Ika: Here we are dealing with a case where the gentile said to the Jew when he returned the money: Place it upon the ground and be dismissed, and afterward the other Jew went and took it. Therefore, the loan was transacted directly between the second Jew and the gentile. The Gemara asks: If that is so, what is the purpose of stating it? In this scenario it is obvious that there are two separate loans and the first Jewish lender has nothing to do with the loan to the second. This is certainly permitted.

Rather, Rav Pappa said: It must be speaking about a case where the gentile took the money from the first Jew and gave it to the second Jew by hand. The Gemara asks: But still, what is the purpose of stating it? In this case also, the second loan is clearly transacted directly with the gentile lender. The Gemara answers: Lest you say: The gentile himself, when he does this, he gives it with the knowledge of the Jew, as he trusts the second borrower due to the mediation of the first, and therefore one might have thought he is deemed involved in the loan. To counter this, the baraita teaches us that this is not the case.

Rav Ashi said: It is possible to explain the baraita in a different way. When we say that the halakha is that there is no agency for a gentile, this matter applies concerning the separation of teruma, the portion of produce designated for a priest. It is in this context that the halakha that there is no agency for a gentile is derived, but concerning the rest of the halakhot of the Torah, there is agency for a gentile.

The Gemara comments: And this opinion of Rav Ashi is an error, since what is different about teruma that a gentile cannot be appointed an agent? As it is written concerning teruma: “So you also shall set apart a gift unto the Lord of all your tithes” (Numbers 18:28); once the verse states “you,” the addition of the word “also” in the phrase “you also” serves to include an agent. The Sages additionally derive: Just as you, those who appoint agents, are members of the covenant, i.e., Jews, so too, your agents must be members of the covenant. A gentile cannot separate teruma even if appointed as an agent by a Jew.

The Gemara continues: The concept of agency with regard to the rest of the halakhot of the Torah is also a matter we learn through tradition by a derivation from teruma, as this is the source for the halakha that the legal status of one’s agent is like that of himself. Therefore, the same halakhot apply to agency in all matters. Rather, it must be concluded that the opinion expressed by Rav Ashi is an error.

There are those who say a different version of this discussion: Rav Ashi said: When we say that there is no agency for a gentile, this matter applies concerning them serving as agents for us, but we can be agents for them. With regard to this comment it was said: And this opinion of Rav Ashi is an error, as what is different that they cannot serve as agents for us? As it is written concerning teruma: “So you also shall set apart a gift unto the Lord of all your tithes” (Numbers 18:28). Once the verse states “you,” the addition of the word “also” in the phrase “you also” serves to include your agents. The Sages also derive: Just as you, those who appoint agents, are members of the covenant, i.e., Jews, so too, your agents must be members of the covenant.

The Gemara continues: Therefore, we also cannot serve as agents for them, because the same principle is said: Just as you, those who appoint the agents, are children of the covenant, so too, all who appoint agents must be members of the covenant. Rather, it must be concluded that this opinion expressed by Rav Ashi is an error.

Ravina says another answer: Granted, a gentile is not included in the category of agency. But he has the power, by rabbinic law, to acquire an item through an act of acquisition performed by another. This is similar to the halakha concerning a Jewish minor. As with a minor, is it not the case that even though he is not included in the category of agency,