Is it permissible to combine a fixed salary and a commission in an employment contract, and what is the correct contract for such cases, especially if the worker contributes only effort and no capital?

The contract established between the questioner and the institution's owner is either a lease contract (ijarah) or a Mudarabah (profit-sharing) contract.

If it is a lease contract, then the wage must be known: - Either it is a fixed amount. - Or a percentage of the profit. - Or a combination of both.

However, agreeing on a percentage that varies from one situation to another leads to ambiguity (Jahalah), which invalidates the contract. In such a case, the worker is entitled to a wage equivalent to what is customary for the work performed in the past.