Chapter on Prohibited Forms of Sale

Allah, exalted be He, has permitted His servants to buy and sell so long as that does not cause them to forfeit something more beneficial and more important—such as crowding out the performance of a mandatory act of worship—or bring harm to others.

Accordingly, any sale or purchase concluded by a person on whom the Friday prayer is obligatory, once the second call to prayer has been given, is invalid. Allah, the Exalted, says: “O you who believe, when the call is made for prayer on Friday, hasten to the remembrance of Allah and leave off trade; that is better for you, if you but knew” (Q 62:9). Thus Allah expressly forbids trade at the time of the adhan for the Friday prayer so it will not become a pretext for people to busy themselves with commerce instead of attending. He singled out trade because it is among the chief means by which people earn a living, and the prohibition entails that any such sale is unlawful and void. He then says: “That”—meaning leaving off trade and attending the Friday service—“is better for you” than occupying yourselves with buying and selling, “if you only knew” what truly benefits you. The same applies to any other activity that distracts from the prayer: it too is forbidden.

The same ruling extends to the remaining obligatory prayers: one may not occupy himself with trade to the detriment of performing them.