Riba equal quantities of the same kind of commodity ("like for like") — for example 100 kilograms of wheat for 100 kg of wheat — in a riba-free transaction called for by quoted ahadith. Or how "divine law" could prescribe that a jeweler — "who has spent his time and effort to convert gold into jewelry" and is taking gold as payment — not be compensated? M.A. Khan also notes that the authors of the IIIE blueprint have no objection to traders selling higher purity/quality commodity for cash and using the proceeds to buying more less purity/quality commodity, and wonders what
Commodity (Marxism) of value, product-values in an open market are regulated by the average socially necessary labour time required to produce them, and price relativities of products are ultimately governed by the law of value. Commodity-trade, Marx argues, historically begins at the boundaries of separate economic communities based otherwise on a "non-commercial" form of production. Thus, producers trade in those goods of which those producers, have episodic or permanent surpluses to their own requirements, and they aim to obtain different goods with an equal value in return. Marx refers to this as "simple exchange" which implies what Frederick Engels calls "simple commodity