The Shaykh (al-Gharyānī) wrote:
“If a contract is concluded whereby a Muslim renders personal services to a kāfir, it is rescinded by operation of the law. After it has been in existence and given effect to, the hireling who has provided the services is entitled to the average fee paid to his like, since the contract is void (bātil).”
I (= al-Majjājī) commented:
“There is no point in reverting him to the average fee in this case. This lease of human services (ijārah), in fact, is vetoed neither due to a defect in the stipulated fee (ujrah) nor in the benefit extended to the lessee (manfa`ah) as such. It is in fact only vetoed because of a meaning extrinsic to the pillars of the contract, namely, the humiliation the kāfir inflicts on the Muslim by the latter serving him, together with the foreseeable risk that he will harm the Muslim, feed him prohibited substances, and prevent him from some obligations, such as the fast and the prayer.
The like of this is prohibited at source, i.e. to start with, and if it nevertheless occurs, the Muslim involved is sinful yet entitled to receive the agreed upon fee, inasmuch as it is a quid pro quo for a benefit essentially permissible, the provision of which is forbidden due to the contingent element of kufr.
Ibn Rushd (in Al-Bayān wa at-Tahsīl) divided the lease of a Muslim’s services to a kāfir into four categories in terms of the applicable ruling, listing the category we examined here as part of the forbidden variety, and adding: “This type of lease is rescinded if discovered; otherwise, if time elapses over it, it is given effect to and the lessor is entitled to his fee”.”