What is the ruling of the Shari'ah on deducting a portion of an employee's salary monthly in exchange for their treatment at a private medical facility with which the company contracts, with the company paying the remaining portion, knowing that this serves a general interest for the employees?

If the intention is for the worker to pay a portion of the medical service cost and the company to bear the remainder, then there is no objection. However, if it is a health insurance service, then we elaborate: If it is cooperative insurance based on mutual support, where the company deducts an amount from employees' salaries along with a donation from the company, then this is permissible. But if it is commercial insurance in which the company pays an amount to a healthcare provider for the treatment of workers, then it is forbidden, based on gharar (excessive uncertainty) and maysir (gambling), and it is not permissible to participate in it except for someone who is compelled, and in this case, one benefits only to the extent of what was paid. The alleged benefit in commercial insurance is not considered a justification for its permissibility, because it is a nullified benefit that the Sharia has invalidated.