What is the ruling on one who lent to another and stipulated an increase in the repayment? Is it permissible for him to return only the borrowed amount without the increase?

The questioner : The Shaykh, may Allah reward you. A person borrowed money with riba, for example, borrowing ten and owing thirteen. He is in debt. Does he have to pay the riba?

The Shaykh : If you are in a country where, if they go to the judge, the riba is prevented, then do not take it. Pay back the principal, the capital, and do not pay the rest. If you are in a country where that does not help, then look at the public benefit.