The Ruling on Selling Gold on Installment

Question:
We received this question from Abu 'Abd al-'Aziz from Unayzah. He says: Shaykh, a man sold gold to another man on installment, and both of them were unaware of that. What is required of them after they have learned of the prohibition of that? It is known that the buyer still has three installments remaining that he will pay to the seller.

Answer:
This transaction is invalid and the contract is not valid. So the one who has the gold must return it to its owner, and the one who has the money must return it to its owner, and they must conclude a new contract. They must not separate while there is anything between them. The seller receives the value from the buyer, and the buyer receives the commodity, which is the gold, from the seller, in one place. The saying of the Messenger (peace and blessings be upon him) weight for weight, hand to hand, means mutual exchange. Yes.