Is an employer sinful who deducts ten days from the salary of a worker who worked for him for 27 days, because the worker left the job without prior notice, knowing that the working conditions were not in compliance with the laws?

The judiciary is the competent authority for settling disputes, because it is more capable of hearing the parties and understanding the facts and evidence, whereas the mufti (definition) only hears from one party. In general, an employer has the right to withhold a worker's wages if the worker leaves the job before the contract term ends without an excuse, as he is not entitled to wages for what he refrained from doing, as mentioned by Ibn Qudamah.