Yahya related to me from Malik from Ibn Shihab from Malik ibn Aus ibn al-Hadathan an-Nasri that one time he asked to exchange 10O dinars. He said, "Talha ibn Ubaydullah called me over and we made a mutual agreement that he would make an exchange for me. He took the gold and turned it about in his hand, and then said, I cant do it until my treasurer brings the money to me from al-Ghaba. Umar ibn al-Khattab was listening and Umar said, By Allah! Do not leave him until you have taken it from him! Then he said, The Messenger of Allah, may Allah bless him and grant him peace, said, "Gold for silver is usury except hand to hand. Wheat for wheat is usury except hand to hand. Dates for dates is usury except hand to hand. Barley for barley is usury except hand to hand." "Malik said, "The commentary on why that is disapproved is that the owner of the good gold uses the excellence of his old gold coins as an excuse to throw in the unminted gold with it. Had it not been for the superiority of his (good) gold over the gold of the other party, the other party would not have counterpoised the unminted gold for his kufic gold, and the deal would have been refused. "It is like a man wanting to buy three sa of ajwa dried dates for two sa and a mudd of kabis dates, and on being told that it was not good, then offering two sa of kabis and a sa of poor dates desiring to make the sale possible. That is not good because the owner of the ajwa should not give him a sa of ajwa for a sa of poor dates. He would only give him that because of the excellence of kabis dates. "Or it is like a man asking some one to sell him three sa of white wheat for two and a half sa of Syrian wheat, and being told that it was not good except like for like, and so offering two sa of wheat and one sa of barley intending to make the sale possible between them. That is not good because no one would have given a sa of barley for a sa of white wheat had that sa been by itself. It was only given because of the excellence of Syrian wheat over the white wheat. This is not good. It is the same as the case of the unminted gold."