What is the ruling on the wage received by a daily laborer for providing workers to the owner of a tractor, without working alongside them, in order to increase his income?

It is permissible for the questioner to agree with the tractor owner to bring laborers and receive a known wage, even if his wage is equivalent to that of one of them. However, if his daily work is for another person, with a wage and at a specific time, then he is not allowed to do another job during that time except with the permission of his employer, because the time and benefits of the private employee during the period of hire belong to the employer. Scholars have defined the private employee as one who works for a single individual for a temporary job or one whose benefit is estimated for a specific period, and he is not allowed to work for anyone other than his employer because his benefits during that period become due to him.