Is it permissible for a free Muslim man to be hired to perform Jihad?
General Chapter
Al-Mughni
Book of Jihad
Primary text
The hiring of free Muslim men for Jihad is invalid because military service becomes an individual obligation upon those qualified to undertake it. Once the obligation is determined, one is not permitted to perform it on behalf of another, similar to how one cannot perform the obligatory Hajj for someone else. This is the position of Al-Shafi'i.
Supporting text
If the hiring is deemed invalid, the contract is void, the wage must be returned, and the fighter is entitled to his determined share because his fighting occurred without a wage agreement.