the contract follows that custom even if they do not expressly articulate it.

The adherents of al-Shafiʿī have agreed with this, though they set the principle aside in some issues and carry it through in others.

All the jurists are in accord that it is applied to the currency current in the land when concluding exchanges—even when no condition is voiced—treating common usage as though it were an express stipulation. The same holds for the customary manner of delivery (1) even when left unmentioned, as when someone sells or buys a house that contains a great deal of furniture that cannot be moved in a day or two. They also invoke it when accepting gifts brought by children, deeming their word sufficient, and when entering a man’s house on the strength of those children’s report that he has granted permission. Similar examples are many.

The principle is rejected, however, by those who say that no wage is due to the bathhouse keeper, the baker, the cook, the washer, or the muleteer until a formal contract of hire is concluded with them.

Yet the Qur’an, the Sunnah, and scholarly consensus establish that a marriage contract is valid even when no dowry is named, and that the customary dowry (mahr al-mithl) then becomes obligatory. If this is allowed in marriage—a contract for which the law exercises a degree of caution unmatched elsewhere (2), and in which the conditions agreed upon are most entitled to fulfillment—then other contracts deserve that latitude even more.

Accordingly, if the contestants have an established custom regarding the distance between the shooting line and the target, the size of the target, or the height at which the butt is set, the contract is interpreted in light of that custom (3), and there is no need to spell it out.