Sayyiduna Malik bin Aws bin Hadthan says: I engaged in a currency exchange of silver for gold with Sayyiduna Talhah bin Ubaidullah (may Allah be pleased with him). He said: Grant me respite until my clerk returns from Ghabah. But Sayyiduna Umar bin Khattab (may Allah be pleased with him) heard this and said: No, by Allah! You cannot separate from them before taking the coins in exchange, because I heard the Messenger of Allah (peace and blessings be upon him) say: Trading silver for gold is usury, except when it is hand to hand.