a condition that contradicts the requirement of the contract, and therefore it is invalid, just as if he stipulated that he may sell it whenever he wishes. Furthermore, because it is the removal of ownership to Allah Almighty, it is not valid to stipulate an option (khiyar) in it, like the manumission of a slave (itq). Also, because it is not a contract of exchange, stipulating an option in it is not valid, like in a gift (hiba). It differs from a lease, as that is a contract of exchange, and it is a type of sale. Moreover, when an option enters into a contract, it prevents the establishment of its ruling before the expiration of the option or the act of disposal; here, if the option were to be established, it would be established alongside the establishment of the ruling of the endowment, and it would not prevent disposal, so the two cases differ.

Section: If he stipulates in the endowment that he may remove whomever he wishes from the beneficiaries of the endowment, and admit whomever he wishes from others, it is not valid; because this is a condition that contradicts the requirements of the endowment, thus rendering it corrupt, just as if he stipulated that he should not benefit from it. If he stipulates for the manager that he may give to whom he wishes among the beneficiaries of the endowment and exclude whom he wishes, it is permissible; because this is not an exclusion of the beneficiary (mawqoof 'alayh) from the endowment, but rather he has linked the entitlement of the endowment to a specific quality. It is as if he granted him a right in the endowment if he possesses the quality desired by the manager for his gift, and did not grant him a right if that quality is absent in him. This resembles the case where he endows it upon those among his offspring who are engaged in religious studies; those who are engaged in it are entitled to it, unlike those who are not. If the one engaged in it ceases his engagement, his entitlement is removed, and if he returns to it, his entitlement returns. And Allah knows best.

Section: If he designates the upper floor of his house as a mosque to the exclusion of the lower floor, or the lower floor to the exclusion of the upper floor, it is valid. Abu Hanifa said: It is not valid, because a mosque is followed by its airspace. Our evidence is that its sale is valid, so its endowment is also valid, like the house as a whole. Additionally, it is an act of disposal that removes ownership to one for whom the right of stability and disposal is established, so it is permissible in what we mentioned, like a sale.