for the surplus is nothing but payment for the delay, and Mālik paid no heed to the fact that the contract was couched in the language of “sale.” Ibn ʿAbd al-Ḥakam and others relate this from him. Likewise, there is no good in handing over a garment for cash in return for an identical garment on credit when the transaction is framed as a sale. By the same token, it is not permissible to exchange one shaṭarī garment for two shaṭarī garments on deferred terms, whereas there is no harm in selling a shaṭarī garment for immediate delivery against two marwī garments to be delivered later.

In brief, one may deliver coarse linen for its fine counterpart and fine linen for its coarse—two for one or one for two. The same applies to cotton and wool fabrics: their fine may be exchanged for their coarse and their coarse for their fine. No attention is paid to the sameness of their names when their utilities differ and people’s purposes in them diverge. Similarly, a literate, skilled, and eloquent slave may be exchanged for several foreign, unskilled slaves, because the objective is different.

Conversely, Mālik and his companions consider it impermissible to sell, on credit, anything that is produced from the very item handed over immediately, when that item is the source from which the deferred commodity is derived. Thus wool may not be advanced for a woolen garment or for flax, nor may khazz or silk, or qasīl (green barley fodder) and shaʿīr (barley grain), be traded in this fashion. None of these arrangements is allowed unless the deferment is so short that there is no possibility of weaving that flax into a linen garment or of that barley turning into qasīl during the interval; in that case the transaction is, in effect, hand-to-hand.

However, it is lawful to transact in things that have already separated from their source. Accordingly, there is no objection to bartering qasīl for barley, whether for cash or on deferred terms, provided the qasīl is delivered immediately and the barley later. The same applies to a garment delivered for cash in exchange for flax, wool, or silk to be delivered subsequently. And when the genera differ, no problem arises at all; for example, it is permissible to advance