Shimon borrowed $100 from Yehuda for a week.
At the end of the week Shimon called Yehuda. “I’ll be passing by your house this afternoon,” he said. “I have an envelope with the money. Will someone be home?”
“No one will be home till about 8,” replied Yehuda. “If you want, you can put the envelope through the mail slot.”
“Okay,” agreed Shimon.
Yehuda returned home that evening. He picked up the mail that lay scattered on the floor: some bills, a wedding invitation, and several tzedakah requests.
At 9 p.m. Shimon called. “Did you get the envelope with the money?” he asked.
“There was no envelope with money,” Yehuda replied. “Did you put it through the mail slot?”
“Most definitely!” answered Shimon. “Maybe one of the household members took it?”
“No, I came home first,” Yehuda said. “The mail was scattered on the floor, but no envelope with money.”
“Let’s wait till Shabbos,” suggested Shimon. “Maybe it will turn up.”
“Not likely…” replied Yehuda. “But I’m willing to wait.”
On Motzaei Shabbos, Yehuda called Shimon. “Guess what?” he said. “We moved the couch to clean up, and I found the envelope. The cat must have dragged it there.”
“I didn’t know that your cat could hide an envelope,” replied Shimon.
“Neither did I,” acknowledged Yehuda. “Regardless, the envelope had only $80 in it – not $100. Could you have made a mistake?”
“I’m sure that there was $100,” insisted Shimon. “I counted twice before sealing the envelope.”
“I don’t know what to say,” replied Yehuda. “There was only $80!”
The two came before Rabbi Dayan. Yehuda asked, “Does Shimon have to add $20? And what if I wouldn’t have found the envelope?”
“If the borrower slipped payment through the mail slot without prior arrangement, and somehow it got lost in the household shuffle or some other manner, it is unclear whether this is considered valid repayment,” replied Rabbi Dayan. “Although it suffices to return to a secure area of the lender, it may require that he become aware of the payment” (C.M. and Sma 355:1; Aruch HaShulchan 120:2; Pischei Choshen, Halva’ah 5:1[2]).
“However, when the lender agreed to this arrangement, the borrower is exempt, because he cannot expect the borrower to watch the money further (see C.M. and Sma 120:1).
“When the borrower claims that he paid fully, but the lender denies or questions this, the ruling depends upon details of the case.
“If Shimon claims with certainty that the envelope contained the full amount, whereas the lender claims definitively that he did not receive the envelope at all or that it was lacking – this is like any other case in which the borrower claims that he repaid the full amount and the lender denies receiving payment.
“Thus, when the loan was already due and there was no formal loan document, Shimon is believed, but is obligated in a minor (heses) oath. This is because Yehuda is now demanding payment from Shimon, who is in possession – so that the burden of proof is on Yehuda. Beis din almost never administers oaths nowadays, but instead usually advocates a compromise – here leaning toward Shimon, who is exempt, in principle (C.M. 78:3; C.M. 12:2; Pischei Teshuvah C.M. 12:3).
“However, if Shimon is unsure whether the envelope contained the full amount, whereas Yehuda claims definitely that it didn’t – because the debt is clear and Shimon is unsure whether he repaid, Shimon is required to pay the claimed missing amount. Here we say: Ain safek motzei midei vaday, and he remains b’chezkas chiyuv (C.M. 75:9; Pischei Choshen, Halva’ah 2:32).
“If Yehuda is also unsure whether he received the envelope or not – or whether it was lacking the full amount – because neither party claims definitively, Shimon is exempt even b’dinei shamayim. However, some say that they should reach an agreement (C.M. 75:18; Shach 75:65; Pischei Choshen, Halva’ah 2:31-32].
“Because this arrangement can potentially lead to disputes even among honest people,” concluded Rabbi Dayan, “it is best to hand payment directly and count the money in each other’s presence, when possible.”
Verdict: If the borrower returned the money through the mail slot with the lender’s consent, he is exempt. If there is a dispute whether the envelope contained the full amount, this is like other cases of dispute between the lender and borrower regarding whether he repaid fully.
