What is the ruling on repaying a debt with an increase as a gift without it being stipulated?

Question:
May Allah reward you. The questioner says: My friend borrowed a sum of money from me. After a period, I needed this money and asked him for it, and I was in dire need of it. My friend knew this and returned the money to me with an increase, even though I had not stipulated the increase. He told me, "This increase is a gift from me to you, because I know that you are in need of money." Is this riba (usury or interest) or a gift?

Answer:
Yes, this is not riba. Riba is what is stipulated at the time of the contract. If you say, "I am lending you one hundred riyals on the condition that you return one hundred and ten to me," that is explicit riba. But if you lend to him for the sake of Allah, not wanting an increase, but lending to him to meet his need, and then he returns to you the amount he took from you, but he adds to it voluntarily when returning it, then this is good repayment. There is no harm in it. The Messenger (peace and blessings be upon him) said, "The best of you are those who are best in repayment." So this is good repayment, and since it was not stipulated in the contract, there is no harm in it, and it is good repayment.
The Prophet (peace and blessings be upon him) borrowed a young camel from the camels. He borrowed a young camel from the camels, and returned in its place a superior four-year-old camel, and said, "The best of you are those who are best in repayment." So this is good repayment. You may accept it.