Is the contract valid if an infidel tells a Muslim: 'Free your slave on my behalf, and I will pay you its price'?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
If an infidel instructs a Muslim to free his slave in return for payment from the infidel, the contract is valid because the act of freeing the slave is not considered an act of acquiring ownership, but rather the nullification of servitude (رق). Ownership is established only by legal consequence (حكما) in this instance, which is permissible, similar to acquiring ownership through inheritance by legal consequence. Furthermore, the benefit accrued to the slave through manumission overwhelms any harm caused by the momentary technical ownership, rendering the harm negligible.
Supporting text
There is an alternative view suggesting this transaction is invalid, based on the prohibition associated with the purchase of a Muslim relative by an infidel.