just as the spoils of war are gained through the efforts of the combatants and their horses, and wealth acquired without battle is gained through the Muslims’ might and support. This differs from a lease or hiring contract, whose object is the work or usufruct itself. If someone hires another to build, sew, plow or sow land, or harvest a crop, then once the agreed work has been completed, the hirer has obtained what he sought through the contract and the worker is entitled to his wage. Hence, in a binding hiring contract, the work must be precisely specified, just as the item sold must be precisely specified.

Here, however, the use of the laborer’s efforts, his oxen, and his iron implements is comparable to the use of the owner’s land and trees. Neither party seeks merely to obtain the benefit contributed by the other; rather, both seek what is produced by combining their respective contributions. If there is an increase, they share it; if there is none, the benefit contributed by each has gone to waste. They thus share in both gain and loss, like all other partners in whatever increase is produced by the assets they own. This is a class of transactions that differs from a pure lease or hiring contract in its true nature, purpose, and legal implications. To the extent that it contains an element of exchange, that element is of the same kind as the element of exchange found in a partnership.

Transactions founded on justice in this world fall into two categories: exchanges and partnerships.

Exchanges include sales and leases.

Partnerships include co-ownership and contractual partnership.

This includes the Muslims’ joint interest in the public treasury; people’s common access to things open to all, such as the use of mosques, public marketplaces, and roads; land reclaimed from wasteland and other freely available resources that are discovered; the heirs’ joint ownership of an inheritance; the common interests of legatees and endowment beneficiaries in bequests and endowments; and the joint-capital or labor partnerships formed by merchants and artisans, and the like. These two categories are the source from which injustice arises, as Allah Most High said concerning David—peace be upon him—:

“Indeed, many partners wrong one another, except those who believe and perform righteous deeds—and how few they are!” [Sād: 24] [Sād: 24].