Is it permissible for someone to pay off the debts of others—without their knowledge—using money earned from bank interest, in order to protect the debtor from harm, regardless of whether these debtors are in hardship or are procrastinators?

Usurious gains are illicit money that must be disposed of by spending it on Muslim welfare or by giving it to the poor and needy. It is permissible to use it to pay off the debts of poor debtors. It becomes permissible for the poor person, but this disposal is not intended as charity. Usury is one of the gravest sins, and its perpetrator must perform sincere repentance and rid himself of the illicit money he possesses.