The Torah in Parashat Mishpatim presents the command of “lo tiheyeh lo ke-nosheh” (22:24), which the Gemara (Bava Metzia 75b) interprets as forbidding a lender from pressuring or even subtly asking the borrower to repay the loan if he is incapable of repaying. This prohibition is listed by the Rambam as one of the Torah’s 613 commands (lo ta’aseh 234), and is codified in the Shulchan Arukh (C.M. 97:2), who writes, “It is forbidden to pressure the borrower to repay if he [the lender] knows that he does not have [with what to repay], and it is forbidden even to appear before him, because he is ashamed when he sees the lender and he cannot afford to repay.”
The Minchat Chinukh (67) notes the implication of the Shulchan Arukh’s ruling that this prohibition applies only if the lender knows for certain that the borrower is unable to repay the loan. But if he is unaware of the borrower’s financial situation, and as far as he knows, the borrower might be in a position to repay, then he is permitted to remind the borrower to pay the money. This is the conclusion of Rav Avraham David of Butchach, in his Kesef Ha-kodashim (97:2).
By contrast, Rav Eliezer Papo, in his Pele Yoetz (“chov”), writes:
One who is owed by his fellow is commanded not to claim his fellow…if he knows he does not have [the ability to repay]… Even if he suspects him of being dishonest, that he has [enough money] but pretends he does not, still, he must be concerned that perhaps he is honest, and he should be fearful of violating [this prohibition]…until it is clear to him that he has money or assets – either real estate or moveable items – with which to repay his debt. Then he is not obligated to pity him…
Rav Papo writes explicitly that the prohibition of “lo tiheyeh lo ke-nosheh” applies in any case when the borrower is unable to pay, and therefore, a lender must not claim the debt until he has ascertained that the borrower is in a position to pay. Otherwise, he must be concerned about potentially violating this prohibition, which depends solely on the borrower’s financial situation, and not on the lender’s knowledge of the borrower’s financial situation. This ruling is in contrast to the implication of the Shulchan Arukh, and the ruling of the Kesef Ha-kodashim, that the Torah prohibition does not apply unless the lender knows for certain that the borrower does not have the means with which to repay the loan.
Rav Asher Weiss, in one of his published responsa (Minchat Asher 2:102), concurs with the position of the Kesef Ha-kodashim, and thus rules that one is permitted to ask a borrower to repay the loan unless he has definitive knowledge that the borrower is unable to do so. The question which Rav Weiss addresses in this responsum was posed by somebody who runs a gemach (free loan service), whose beneficiaries very often do not repay the loans on time. This man wanted to know whether he was permitted to periodically remind or urge the beneficiaries of this service to repay their loans, or if this violated the prohibition of “lo tiheyeh lo ke-nosheh.” Rav Weiss, following the view of the Kesef Ha-kodashim, ruled unequivocally that he was permitted to do so, unless he had specific knowledge about a borrower that he does not have the ability to repay.