the lessee and the lessor would both be exposed to gain or loss because of this uncertainty. It is also supported by the hadith of Abu Hurayrah, may Allah be pleased with him, that the Prophet, peace and blessings be upon him, “forbade sales involving uncertainty” (1). Everything unknown involves uncertainty, and a lease is a sale, though it is a sale of benefits. Moreover, if the benefit is unknown, it will lead to dispute and contention, which in turn lead to enmity and hatred.

His statement, “knowledge of the benefit,” means that the benefit must be known, either through verbal specification or through customary practice.

An example of verbal specification is for one to say, “I want such-and-such,” and specify it.

An example of specification by customary practice will come in the author’s discussion.

His statement, “such as occupying a house”: an example of this is when a man rents a house to live in, but the tenant sells donkeys—donkeys being the plural of donkey—and makes the house a stable for them. This is not permissible, because occupying a house means that human beings live in it, not donkeys.

If the tenant wishes to alter the house and says, “This room is narrow, so I will remove the wall between it and the other room, so that they become one large room,” he has no right to do so. He has only the right of occupancy. It is not customary for an occupant to alter the leased property except with the owner’s permission.

His statement, “and the service of a person”: an example is when one hires a person to serve him, and then begins to employ him