wrongdoing toward the people in two respects: first, it wrongs the sellers who wish to dispose of their goods, and second, it wrongs the buyers who wish to purchase from them. When it is impossible to eliminate every form of injustice, one must at least eliminate whatever portion of it can be removed. Accordingly, in this situation price-fixing is mandatory by unanimous agreement. In reality, it is nothing more than obliging the traders not to sell—or to buy—except at the fair market value.

Such compulsion is required in many other areas of the Sacred Law. Just as forcing someone to sell is normally impermissible, yet becomes lawful in certain circumstances—such as obliging a debtor to sell property in order to settle an outstanding debt or to meet a legally binding maintenance payment—so too coercing someone to sell only at the market rate is impermissible except where a valid right exists, and that, too, occurs in several scenarios. Examples include compelling a person who possesses food needed by someone in dire necessity, or obliging the owner of trees or a building erected on another man’s land to accept their market value and no more, so that the landowner may take possession. Many similar cases could be cited.

The same principle underlies the doctrine of “propagation” (sarāyah) in manumission, as in the Prophet’s statement ﷺ: “If a man frees his share in a slave and has sufficient wealth to cover the slave’s full price, the slave is assessed at a just value—neither undervalued nor exaggerated—¹.” He must then pay his partners their shares and the slave becomes fully emancipated; if he lacks the means, only the portion he freed is set free.

Likewise, anyone who is obliged to purchase something for an act of worship—such as a conveyance for the pilgrimage, a slave to emancipate in expiation, or water for purification—must buy it at the going rate; he may not refuse to purchase unless it is offered only at a price he himself chooses. The same applies to food or clothing that a man is duty-bound to provide for dependants: if suitable provisions are available at the customary market price, he may not switch to something inferior until those items are offered at a price he likes. Many further parallels exist.

For this very reason a number of jurists—among them Abū Ḥanīfah and his disciples—prohibited court-appointed surveyors who partition real estate and other property for a fee from forming a cartel when people are in need.