“O you who believe, when you contract a debt for a specified term, write it down. Let a scribe write it down between you fairly, and let no scribe refuse to write as Allah has taught him. So let him write, and let the one upon whom the obligation rests dictate; and let him fear Allah, his Lord, and not diminish anything from it. If the one upon whom the obligation rests is of limited understanding, weak, or unable to dictate himself, then let his guardian dictate fairly. Call upon two witnesses from among your men; and if there are not two men, then one man and two women from among those witnesses whom you approve, so that if one of them forgets, the other may remind her. Let not the witnesses refuse when they are called. Do not grow weary of writing it down, whether small or large, until its due term. That is more equitable in the sight of Allah, more reliable for testimony, and more likely to prevent doubt among you—unless it is an immediate transaction that you conduct among yourselves, in which case there is no blame upon you if you do not write it down. Take witnesses when you enter into a sale, and let no scribe or witness be harmed. If you do so, then it is indeed wickedness on your part. Fear Allah; Allah teaches you, and Allah is Knowing of all things.” (282)
Concerning His words, “O you who believe, when you contract a debt for a specified term”: Ibn Abbas, may Allah be pleased with him, said: “When Allah prohibited ribā, He permitted the advance sale.” He said: “I bear witness that the guaranteed advance sale for a specified term has been made lawful by Allah in His Book, and He has granted permission for it.” He then recited: “O you who believe, when you contract a debt for a specified term, write it down.”
Concerning His words, “when you contract a debt”: that is, when you transact on credit. It is said, “dayantuhu,” when you transact with someone on credit. He said “with a debt” after saying “when you contract,” because a debt transaction may signify mutual requital or reciprocal exchange; so He qualified it with “debt” in order to make the intended meaning of the expression clear. It was also said that it was mentioned