Quran 2:283 – Surah Al-Baqarah (The Cow)

And if you are upon a journey, travelling and you contract a debt, and you do not find a writer, then a pledge (ruhun or rihān, plural of rahn) in hand, as a guarantee for you. The Sunna clarifies the permissibility of making pledges in towns, where writers may be forthcoming; but the stipulation is made in the event of travel because in this case it is more important to have a guarantee; God’s reference to it being ‘in hand’ (maqbūda) is a condition for the pledge given to be valid, and to satisfy the pledgee or his representative. But if one of you, the creditor, trusts another, the debtor, over the debt and does not require a pledge, let him who is trusted, the debtor, deliver his trust, the debt; and let him fear God his Lord, when delivering it. And do not conceal the testimony, if you are summoned to give it; whoever conceals it, his heart is sinful: the heart is mentioned because it is the locus of the testimony, and because if it sins, there are other sinful consequences, and so the person will be punished as though he were a sinner; and God knows what you do, nothing of which can be hidden from Him.