and its weight. Should either party disown the piece that has been returned to him, claiming he does not recognise it, he must swear by Allah that, to the best of his knowledge, he handed over nothing but sound coin and that he does not recognise this piece as one of those he paid; once he has taken that oath he is acquitted.
Mālik further permitted a short-weight, debased dinar to be exchanged—by way of courtesy—for a full-weight, sound dinar, classing the matter as a benevolent loan and an act of kindness. He added that if the deficient coin is actually of finer metal, the exchange is not allowed, for in that case it becomes haggling and a sale.
Most scholars regarded even the first form as disliked and rejected its permissibility. Their argument is that whenever ownership is transferred through the exchange of one article for another, the transaction is no longer a loan; once a counter-value is taken, it is a sale. The Prophet, peace and blessings be upon him, forbade trading dinar for dinar and dirham for dirham except like for like, equal for equal in weight.
Loans have their own rulings and etiquette, and we shall, Allah willing, devote a separate and sufficient chapter to them at the end of this section.
Among the issues on which Mālik—may Allah have mercy on him—differed from all the other jurists is the permissibility of selling a garment for one dinar payable in a month, and of selling one dinar for a specified number of dirhams payable in two months. In his view the sale is actually concluded in dirhams; he pays no heed to defective wording so long as the underlying transaction is sound, just as he ignores fine wording when the underlying practice is unsound. The other jurists see this as a currency exchange that combines heterogeneity and deferment, amounting to two sales wrapped into one.
Mālik also allowed a party to dispose of the price generated by a currency exchange before taking possession, such as when, before the two have separated, he uses that price to purchase a commodity. In his view, this ruling and the one that precedes it belong to the same legal chapter.
It is not permissible to sell silver and gold together for silver, nor to sell mixed gold and silver for gold; nor may either of the two gold species be accompanied by dirhams, any counter-value, food, or condiment. The very same ruling applies to dirham-for-dirham transactions.