perform work he is already obliged to perform; (the second) hiring someone to do what is unlawful for him; and (the third) hiring someone to perform permissible work for an impermissible consideration involving undue uncertainty or something unlawful, or on impermissible terms involving uncertainty or indeterminacy.
As for hiring someone to perform work for which payment is impermissible because he is already obliged to perform it, the contract must be annulled if discovered before the work is done. If the work has already been performed, the worker is entitled to none of the fee, and it must all be returned to the employer if he has paid it.
As for hiring someone to perform work for which payment is impermissible because the work itself is forbidden to him, the contract must likewise be annulled whenever it is discovered. If the work has already been performed, the worker is entitled to none of the fee; it is forfeited and given in charity, subject to the distinctions we explained in the Book of Trade with Enemy Territory concerning a Muslim’s sale of wine to a Christian or another Muslim.
As for hiring someone to perform permissible work for an impermissible consideration or on impermissible terms, the contract must be annulled while annulment remains possible. If the work has already been performed, its assessed value is payable. Allah, through His mercy, grants success.
Section
The Nature of a Reward Arrangement and the Basis for Its Permissibility
A reward arrangement is one in which a person promises another a payment for performing a task for him, provided that he completes it. If he does not complete it, he is entitled to nothing, and his effort goes unrewarded. Mālik and his companions—may Allah be pleased with them all—permitted this for work that yields no benefit to the person offering the reward unless it is completed. This is contrary to the position of Abū Hanīfa and to one of al-Shāfiʿī’s two opinions—may Allah Most High have mercy on them both. By analogy, this involves undue uncertainty, yet the revealed law has permitted it.
The basis for its permissibility is the saying of Allah Most High:
“Whoever brings it will have a camel-load, and I guarantee it.” [Joseph: 72]
It is also supported by the Messenger of Allah’s ﷺ statement on the day of Hunayn:
“Whoever kills an enemy combatant shall have his personal effects.”
And his statement on the day of Badr:
“Whoever does such-and-such shall receive such-and-such, and whoever does such-and-such and such-and-such shall receive such-and-such and such-and-such.”
Although Mālik—may Allah have mercy on him—disapproved of this, his disapproval was only out of concern that