The ruling on repaying a loan with more than what the borrower took

Question:
May Allah reward you. A listener, a Syrian resident in Jordan, sent several questions. In his first one, he says: I have a married sister, and whenever I have money, I give her some of it. One day, when I wanted to travel from Syria, I took gold from her to cover my travel expenses. Is it permissible for me to buy her more gold than what I took from her, or is that considered riba?

Answer:
If she stipulated that you must return it with an increase, returning gold in place of the gold you took from her with an increase, then this is riba and is not permissible. This is by the consensus of the scholars. However, if this was without a condition, and you took it on the basis that you would return its like by weight without an increase, but you increased it from your own side as a form of good faithfulness, then there is no harm in that, due to the saying of the Prophet (peace and blessings be upon him)
And when the Prophet (peace and blessings be upon him) borrowed a camel and wanted to repay it from the camels of zakah, the one whom the Prophet (peace and blessings be upon him) ordered to repay this loan said, "I did not find anything except a superior four-year-old camel." So he (peace and blessings be upon him) said to him, "Give it to him," because he borrowed a one-year-old camel and returned in its place a superior four-year-old camel, which is better than it. So the Prophet (peace and blessings be upon him) said, "Give it to him" . The result is that if this is without a condition at the time of the loan, there is no harm in it. Yes.