The ruling on repaying a debt with an increase as a reward to the creditor

Question:
May Allah reward you. 'Abd al-Aziz Hajji says: I borrowed money, and when I repaid it, I gave him the money plus an increase as a reward for him. Is this permissible, or is it riba (usury or interest)?

Answer:
If this was without any condition, then it is a voluntary gift from the borrower, and the lender did not stipulate it, so there is nothing wrong with it. This is part of good repayment. The Prophet (peace and blessings be upon him) was known for good repayment, and he said, “The best of you are those who are best in repaying their debts.” He would also increase the amount of the loan out of his generosity (peace and blessings be upon him). However, if the lender stipulates the increase, then this is riba (usury or interest), explicit riba, and it is not permissible. Yes.