Is it permissible for a Riyad Bank customer to benefit from a financial reward of 600 Saudi Riyals offered by the bank, knowing that he uses a Visa card issued by the bank and pays for his purchases promptly to avoid usurious interest?

It is not permissible to enter into a credit card contract that entails paying interest (riba) upon delayed payment, because it is not permissible to consent to or sign an interest-based contract. Doing so constitutes an acknowledgment of it and an aid to those who practice it in their sin. The Prophet, peace and blessings be upon him, cursed the one who consumes riba, the one who feeds it, its two witnesses, and its scribe. Any prizes obtained through this forbidden contract are not permissible and must be disposed of by spending them on the welfare of Muslims or giving them to the poor and needy.