As we learned on yesterday’s daf, if someone steals from his friend something that is worth at least a peruta and swears falsely, he is obligated to follow him even to Madai – also known as Medes, part of the ancient Iranian Empire – to return it. Furthermore, he must return it to him personally, and it will not suffice to return it to the victim’s son or to his agent, although he would be allowed to give it to a representative of the court. Our Gemara asks whether an agent who is specifically appointed by someone to accept something on his behalf will have the power to receive payment for him. Rav Ḥisda believes that he can accomplish that; Rabba believes that he cannot.
The Gemara explains Rav Ḥisda’s ruling as based on the fact that if someone goes to the trouble of gathering witnesses to appoint an agent, certainly his intention is to give him the power to act on his behalf. Rabba argues that the man was simply publicly stating that this man is reliable, and that things could be sent with him, but he was not formally charging him with the responsibilities of acting on his behalf to accept payment for him.
Rashi (and most of the other commentaries, as well) understand the Gemara’s discussion to be a debate about establishing agents in general, although the Bartenura suggests that it is limited to the case of our Mishna and discusses only returning stolen objects.
Rashi explains that the difference between Rabba and Rav Ḥisda is whether handing the money (or the stolen object) to the agent is as if he gave it personally to the man himself. This is certainly important according to the Bartenura’s approach that we are focused on the case in the Mishna. According to the other approach, the difference will still be important in a case where the agent does not succeed in getting the money back to the owner. According to Rav Ḥisda, the money was already returned, since the agent represents the owner; according to Rabba, the money has not yet been returned.