The Ruling on Depositing Money in Banks and Taking the Increase

Question:
A man deposited money on a deferred basis in one of the interest-based banks. When he received his principal back, they gave him a profit. He is confused about this profit and does not know what to do with it.?

Answer:
One does not deposit money in interest-based banks except out of dire necessity. If he deposits with them out of dire necessity, he does not take the profit; he does not take the interest, because it is riba (usury or interest), and it is not permissible for him to take riba.
However, some scholars said: If he takes the interest that he did not stipulate, and did not agree with them upon, but they said, "This interest is for you," and he takes it and spends it in a direction of righteousness, such as helping a poor person, repairing a road, or something similar that benefits the Muslims, and he does not consume it, nor does he mix it with his money, but rather spends it in the cause of righteousness, some scholars said: There is nothing wrong with this for the sake of the benefit of the Muslims, and so that the Christians and others do not take it and spend it in disobedience to Allah. This is what some scholars said.
If he takes it, exercises caution, and spends it in a direction of righteousness, and he did not stipulate it with them, nor did he agree to it, then there is a valid position for this. As for agreeing with them on riba, or taking riba for himself, or for his money, or mixing it with his money, this is not permissible.

Question: And what if it was out of ignorance, O Shaykh?

Answer: Even if it was out of ignorance, he does not take it.

Question: And what if he has already taken it?

Answer: He gives it in charity to the poor and the needy.