Question: An employee was tasked by the state to put out a tender for a school or the like. This employee went to some contractors and agreed with one of them to carry out the project for a certain amount, on condition that the employee receive a known portion of that amount. Is it permissible for the employee to do that? And is it permissible for the contractor as well?
Answer — and Allah is the One who grants success: It is obligatory upon the employee to exert himself in the task entrusted to him. If he offers the tender to the contractors considered competent for such work and strives in negotiating the prices, then he must award it to the one who offers the highest price [i.e., the best value to the state under the prevailing procurement rule intended here]. It is not permissible for him to award it to the lower bidder for the sake of getting back a specified portion.
Yes: it may be permissible for the employee to receive a portion from the contractor if, after diligent negotiation, the contractors’ bids are equal. In such a case, it is permissible for him to take a gratuity from the one who receives the contract.
We said it is impermissible as in the question because the employee is an agent; the agent is a trustee, and the trust must be rendered to both the righteous and the wicked. In the hadith: “Do not betray the one who betrays you.” And Allah Most High said: “Indeed, Allah does not like traitors.” [Al-Anfal:58] There are many verses in this chapter.
As for the contractor, it is permissible for him to give the employee something in return for being awarded the contract; the contractor is taking what he takes in exchange for his work.
Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2