Reducing the agreed-upon wage after the work is completed

Question:
Honorable Shaykh, a man hired a worker for a specific job, and they agreed on the wage for the work. After the work was finished, the employer realized that the wage he had set was high, so he was angry about it. He asked the worker to reduce the amount in exchange for the work he had done. Is the employer sinful for changing the agreed-upon wage, since a lease contract is a binding contract?

Answer:
The default is that it is obligatory to fulfill contracts. Allah the Exalted said: Therefore, he must fulfill the contract. However, if he claims that there is excessive loss (gharar) in the contract, this requires proof. In this matter, he should refer to the judge or the court. If they reach a settlement between themselves, then settlement is permissible among Muslims. If they dispute, they must refer to the court to examine whether this wage involves excessive loss or not. Yes. And Allah the Exalted knows best, and may Allah send prayers and peace upon our Prophet Muhammad.