The ruling on earnings resulting from violating the condition of full-time commitment to a company

Question:
A letter reached the program from one of the listening brothers, containing a number of questions. In one of them, he asks and says: If a man contracts with a company, and this company conditions that he not work for another entity, and he performs the work for this company, and then works elsewhere, is the money he earns forbidden? Or is it lawful?

Answer:
The Prophet (peace and blessings be upon him) said: So if you contract with him that he will work with you for such and such hours, and not work with anyone else, and he commits to that, then it appears that he is bound by it; because his work with others may harm their work, it may tire him out, he may come in while exhausted, and he will not be sincere in the work.
So the result is that if he committed to the condition, he does not have the right to do that, and the money he took by this means is not lawful; because he took it without right, and the Messenger (peace and blessings be upon him) said: Yes.

The presenter: May Allah reward you with good, and may He do you good.