Al-Muwatta Hadith 31.39

Yahya related to me from Malik that Yazid ibn Abdullah ibn Qusayt saw Said ibn al-Musayyab sell gold counterpoising for gold. He poured his gold into one pan of the scales, and the man with whom he was counterpoising put his gold in the other pan of the scale and when the tongue of the scales was balanced, they took and gave. Malik said, "According to the way things are done among us there is no harm in selling gold for gold, and silver for silver by counterpoising weight, even if 11 dinars are taken for 10 dinars hand to hand, when the weight of gold is equal, coin for coin, even if the number is different. Dirhams in such a situation are treated the same way as dinars." Malik said, "If, when counterpoising gold for gold or silver for silver, there is a difference of weight, one party should not give the other the value of the difference in silver or something else. Such a transaction is ugly and a means to usury because if one of the parties were permitted to take the difference for a separate price, it could be as if he had bought it separately, so he would be permitted. Then it would be possible for him to ask for many times the value of the difference in order to permit the completion of the transaction between the two parties. Malik said, "If he had really been sold the difference without anything else with it, he would not have taken it for a tenth of the price for which he took it in order to put a 'legal front' on the transaction. This leads to allowing what is forbidden . The matter is forbidden." Malik said that it was not good when counterpoising to give good old gold coins and put along with them unminted gold in exchange for worn kufic gold, which was unpopular and to then treat the exchange as like for like. 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." Malik said, "Where gold, silver and food, things which should only be sold like for like, are concerned, something disliked and of poor quality should not be put with something good and desirable in order to make the sale possible and to make a bad situation halal. When something of desirable quality is put with something of poor quality and it is only included so that its excellence in quality is noticed, something is being sold which if it had been sold on its own, would not have been accepted and to which the buyer would not have paid any attention. It is only accepted by the buyer because of the superiority of what comes with it over his own goods. Transactions involving gold, silver, or food, must not have anything of this description enter into them. If the owner of the poor quality goods wants to sell them, he sells them on their own, and does not put anything with them. There is no harm if it is like that."