When lending money, should the lender trust that the borrower will remember the loan and repay it, or is there a need to create a record attesting to the loan?
Our Gemara brings a teaching by Rav Yehuda in the name of Rav that if someone lends money without having witnesses to the transaction, he transgresses the prohibition of lifnei iver lo titen mikhshol – do not put a stumbling block before the blind (Vayikra 19:14). Reish Lakish, quoting a passage in Tehillim (66:11) adds that he brings a curse upon himself, since if the borrower denies receiving the loan, people will curse the lender, accusing him of falsely claiming that he is owed money.
As an example of these teachings, the Gemara tells that Ravina was presented to Rav Ashi as someone who carefully follows all of the rulings of the Sages. In an attempt to test him, one Friday afternoon – when all are busy and it is difficult to make complicated arrangements – Rav Ashi asked Ravina for a loan, claiming that he had an immediate business opportunity. Ravina responded by asking Rav Ashi to arrange for witnesses to see the transaction and write a promissory note. In answer to Rav Ashi’s question “even me!?” (i.e. am I not trustworthy to pay back a loan?) Ravina explained that especially someone who is focused on his study may forget about something as prosaic as a loan, which would lead Ravina to bring a curse upon himself.
The Meiri argues that we should not accept Ravina’s statement literally, and that there is no reason to be more concerned that scholars will not pay their debts than will ordinary people. It should be noted that Ravina only offered one of the reasons for refraining from making a loan without witnesses – that he would bring a curse on himself. It would appear that he did not want to invoke the prohibition of lifnei iver, since he did not want to be in a position of accusing Rav Ashi – who initiated the loan – of transgressing the prohibition.