Malik b. Aus b. al-Hadathan reported: I came saying who was prepared to exchange dirhams (for my gold), whereupon Talha b. Ubaidullah (Allah be pleased with him) (as he was sitting with ‘Umar b. Khattib) said: Show us your gold and then come to us (at a later time). When our servant would come we would give you your silver (dirhams due to you). Thereupon ‘Umar b. al-Khattib (Allah be pleased with him) said: Not at all. By Allah, either give him his silver (coins) or return his gold to him, for Allah’s Messenger (may peace be upon him) said: Exchange of silver for gold (has an element of) interest in it. except when (it is exchanged) on the spot and wheat for wheat is an interest unless both are handed over on the spot: barley for barley is interest unless both are handed over on the spot; dates for dates is interest unless both are handed over on the Spot.
Chapter : He (the Holy Prophet) cursed the one who accepts interest and the one who pays it.