of the merits of the Sacred Law. This is because a person may need to live in a house but lack the means to purchase it; he then has no option but to rent it. Likewise, the owner of the house may retain ownership of it and wish to benefit from it rather than leave it unused, and he has no means of doing so except by leasing it out. Since the benefit to both tenant and landlord is clear, and there is neither injustice nor usury involved, it is among the merits of the purified Sacred Law that leasing be permitted.

However, it must fulfil certain conditions. Every type of contract has conditions that are mentioned for it, and each of these conditions must be supported by evidence; otherwise, the basic principle is that no such condition exists and that the matter is permissible without restriction. Thus, if anyone claims that a particular sale contract is unlawful, we say to him: Produce the evidence, for the basic principle regarding a sale contract is permissibility. Hence, the conditions that scholars mention for contracts must have proof; otherwise, they are not accepted.

It is valid subject to three conditions: knowledge of the benefit, such as occupying a house, the service of a person, and teaching knowledge.

His statement, “It is valid subject to three conditions,” informs us that a leasing contract may be either valid or invalid. Whatever conforms to the Sacred Law is valid, while whatever contradicts the Sacred Law is invalid. If the leasing contract is invalid, its contractual stipulations do not take effect; rather, the customary equivalent wage becomes due.

His statement, “knowledge of the benefit”: this is the first condition—that the benefit be known to both parties, the lessor and the lessee. Its opposite is an unknown benefit. The evidence for this condition is the saying of Allah, Exalted is He: ⦗⦘ [Al-Māʾidah 5:90–91]. The indication from the verse is that, when the benefit is unknown, it becomes a form of gambling, because