It is authentically established that the Messenger of Allah—may Allah bless him and grant him peace—said, “Usury occurs only through deferment.” 1 It is also authentically established from him in the hadith of Ubādah ibn al-Sāmit and others that usury may arise through either deferment or excess2.
After Ibn Abbās, the scholars unanimously agreed that usury is of two kinds: usury involving excess and usury involving deferment. Ibn Abbās, however, maintained that usury occurs only through deferment. For example, if you sold one sāʿ (dry measure) of wheat for two sāʿs, hand to hand, there would be no harm in it according to Ibn Abbās, because he held that usury occurs only through deferment.
Likewise, if you sold, for example, one mithqāl (unit of weight) of gold for two mithqāls of gold, hand to hand, he did not regard it as usury. But if taking possession were deferred—so that you gave me the one mithqāl while I did not give you the countervalue until after