Is knowledge (*'ilm*) of the consideration (*'iwad*) required in an *ijarah* (lease/hire) contract?
General Chapter
Al-Mughni
Book of Leasing
Primary text
Knowledge of the consideration in a contract of exchange (*mu'awadah*) is a requisite condition. This is established by analogy with the price (*thaman*) in a sale contract. Evidence supporting this is derived from the narration where the Prophet (PBUH) stated, "Whoever hires a laborer, let him inform him of his wage." Knowledge of the consideration is established either by sight or by description, identical to the rules in a sale contract.
Supporting text
If the consideration is known by sight but its measure (*qadr*) is unknown, such as a pile (*sabra*) of grain, there are two views. The stronger view permits it because it is a known consideration permissible in a sale contract, thus making it permissible in an *ijarah*. The opposing view rejects it because the contract might dissolve after the pile is destroyed, leaving uncertainty regarding the amount of return, thus requiring the measure to be known, similar to the consideration in *salam* (advance payment for future delivery).