when people are in need; for if they join forces they drive their fee sky-high. It is therefore even more imperative to forbid sellers who have conspired not to sell except at a price they themselves have fixed. The same holds for buyers who agree among themselves to pool their purchases, for when they combine in order to depress the value of other people’s goods, intervention is even more necessary. Thus, if a group engaged in buying or selling a certain commodity colludes to acquire what it buys for less than the recognised market rate, to sell it on for more than that rate, and to hoard what it has bought, such behaviour is a graver act of aggression than intercepting merchandise before it reaches the market, than the town-dweller’s selling on behalf of the bedouin, or than fraudulent bidding (najsh). They have agreed to wrong the public, forcing people either to sell their goods or to purchase them at prices above the norm, even though the populace needs those commodities and the trade in them.

Whatever goods the general public needs to buy and sell must not be traded for anything other than the customary price whenever the need to exchange them is universal. The same principle applies when people depend on certain crafts—such as farming, weaving, or building—for people must have food to eat, clothes to wear, and homes in which to live. If enough clothing is not brought in—just as, in the Prophet’s time ﷺ, garments were imported to the Ḥijaz from Yemen, Egypt, and Syria, whose inhabitants were then unbelievers—the Muslims would wear what those unbelievers had woven without even washing it. Should a town cease to receive sufficient garments, its inhabitants will need local weavers to supply them. They also require food, whether shipped in from elsewhere or harvested from their own land—the latter being the more common case—and, of course, dwellings, which means they need builders.

For this reason more than one jurist among the Shāfiʿīs and Ḥanbalīs—such as Abū Ḥāmid al-Ghazālī, Abū al-Faraj Ibn al-Jawzī, and others—has stated that these crafts are a farḍ kifāyah (communal obligation),¹ for society’s welfare cannot be secured without them. Jihad is likewise a communal obligation unless it becomes individually binding, as when the enemy attacks a land or the ruler personally summons someone. Seeking knowledge of the Sacred Law is also a communal obligation, except where it becomes individual—namely, each person’s duty to learn what Allah has commanded him and what He has forbidden him.