What is the ruling on working for a company that mediates the employment of programmers for other companies in exchange for a difference in wages, and how can the money earned from it be purified if it is not lawful, and must one leave the job immediately or search for an alternative while having a family and children?

It is permissible for someone who has been hired to perform a task to hire another person to carry it out for a lower wage, unless there was an agreement that he perform it himself, or if his selection was specifically due to his individual person, such as a well-known calligrapher or designer. This is what jurists like Ibn 'Uthaymin have stated, basing their opinion on the permissibility of renting out the remainder of a period for a higher rent.