Nosson and Gabi were counselors together in camp.
One day, while Nosson was out, a friend, Avi, stopped by to visit.
“Hi, Avi!” Gabi greeted him. “What’s doing?”
“Baruch Hashem, things are fine,” answered Avi. “How’s camp? Is Nosson around?”
“Nosson’s out for the day,” replied Gabi. “A family simcha, or something like that, so I’m watching the kids by myself.”
“I hoped I would catch Nosson,” said Avi, disappointed. “I have to talk to him.”
“What’s the matter?” asked Gabi. “Can I help?”
“Nosson owes me $100,” said Avi. “I’d like him to pay me.”
“Nosson mentioned a week days ago that he owes you,” said Gabi. “I gather he hasn’t paid yet?”
“No,” said Avi.
Gabi thought for a minute. “I’ll pay you,” he said. “I see Nosson daily; it will be easier for me to deal with him.”
Gabi took out $100 and gave it to Avi.
“Thanks a lot,” said Avi.
When Nosson returned, Gabi said to him: “Avi came by for the $100 that you owe him. I paid him for you, so you can give me the $100.”
“Who asked you to pay?” replied Nosson. “I didn’t want you to pay for me.”
“What’s the difference?” said Gabi. “You said that you owe him.”
“Yes, but I was hoping to get Avi to cancel the debt,” said Nosson. “I’m tight on money and I’ve done him some favors. What you decided to do is your issue!”
“That may be, but meanwhile you still owe him,” argued Gabi. “I gained you the $100 sitting in your wallet!”
Nosson, however, was adamant that he didn’t want to reimburse Gabi. They decided to bring their dispute before Rabbi Dayan.
“Someone lent Nosson $100,” said Gabi. “I paid instead of him. Does he have to reimburse me?”
“It is morally proper for Nosson to reimburse you, but reimbursement for unsolicited payment of someone else’s loan is not simple,” said Rabbi Dayan. “The Mishnah [Kesubos 107b] teaches that if someone traveled abroad and another person – unsolicited – sustained the wife, the husband is not required to reimburse him. Most Rishonim maintain that this applies also to one who pays his fellow’s debt of his own initiative.” (E.H. 70:8; C.M. 128:1
“However,” continued Rabbi Dayan “Rabbeinu Tam maintains that the Mishnah’s rule applies only to sustenance, since the woman could have minimized her expenses and avoided the need for sustenance. However, payment of a definite debt warrants reimbursement.”
“How do we rule?” asked Nosson.
“Although the Sma [128:3] sides with Rabbeinu Tam, the Shulchan Aruch and Rama rule like most Rishonim,” replied Rabbi Dayan. “Thus, if the borrower refuses to reimburse, we cannot require him to pay.”
“Why should the husband or borrower be exempt, though?” asked Gabi. “The other person covered his expense and caused him gain.”
“There is no actual gain here, only sparing potential loss that is not definite (mavriach ari minichsei chaveiro),” replied Rabbi Dayan. “The husband can claim that the wife would have managed; the borrower can claim that he would have pleaded with the lender to cancel the debt. Alternatively, someone else might have agreed to pay the loan gratis.” (Shach 128:4)
“Are there cases where we do require reimbursement?” asked Nosson.
“There is a dispute regarding a non-Jewish creditor or one who is pressuring, who is unlikely to cancel the loan,” replied Rabbi Dayan. “In addition, some write that the borrower must reimburse if he is in reasonable financial position, so that there is no reason to assume the lender would cancel the debt; or if the borrower indicated he was interested in paying, such as by requesting a loan to pay the debt; or if the other person paid in the presence of the borrower.” (Shach 128:3; Aruch Hashulchan 128:1; Pischei Choshen, Halva’ah 5:34[90,95])