How much effort must a thief expend in returning something that he stole?
According to the Torah (Vayikra 5:21-26) if someone steals from his friend and then lies, swearing that he did not do so, he is obligated to return the money (plus a penalty of an additional fifth) and bring a special sacrifice called an asham gezelot. The Torah emphasizes that it must be returned to the victim, from which the Mishna on our daf, concludes that 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.
The Rambam in Hilkhot Gezela (7:9) explains that he must make a special effort to find the victim and pay him because of the false oath that he took, which convinced the victim that there is no point in seeking repayment. If, however, no oath was taken then the thief can simply wait until the victim comes searching for the stolen object (some suggest that he will be obligated to let the victim know that he is holding the object so that he can come and collect it).
With regard to the leniency allowing the thief to return it to the court, Rashi explains the halakha is interested in saving him the expense of traveling to return an object that may be worth less than the travel costs. The Rosh suggests that this is a form of takanat ha-shavim – a ruling established to encourage people to repent.
During the Mishnaic period, Madai was a far-off city, and getting there was a difficult and time-consuming effort.