as the agreement on estimating its wage and the mutual consent to provide it in exchange for it, it functions like the commencement of the contract for it, becoming like a sale by mutual exchange (al-mu'atah), when a negotiation has taken place that indicates mutual consent to it. Thus, whenever he ceases to embark upon it in a month, the lease for that month is not established due to the absence of a contract. If he cancels, it is likewise; however, it is not truly a cancellation, because the contract for the second month was not established. As for Abu Hanifah, he held the view that if they embark upon the second month, the possession has connected with the invalid contract. This is an invalid excuse, because an invalid contract regarding tangible assets does not become binding upon possession, nor is the specified amount guaranteed. Furthermore, possession here did not occur except for what he already utilized. The statement of Malik is not sound because a lease is one of the binding contracts, so it is not permissible for it to be non-binding.

Section: If he says, "I lease you my house for twenty months, each month for a dirham," it is permissible without any disagreement that we know of, because the period is known and its wage is known, and neither of them has the right to cancel it under any circumstances, because it is one single period, similar to if he had said, "I lease it to you for twenty months for twenty dirhams." If he says, "I lease it to you for a month for a dirham, and whatever is additional is at that same rate," it is valid for the first month because he singled it out in the contract, but it is void regarding the remainder because it is unknown. It is possible that it might be valid for every month he embarks upon, just as if he had said, "I lease it to you each month for a dirham," [because their meaning is the same. If he says, "I lease it to you this month for a dirham," and each month after that for a dirham, or says, "for two dirhams," it is valid for the first, and there are two opinions regarding what follows it.

Section: A lease is a binding contract for both parties, and neither of them has the right to cancel it. This is the view of Malik, al-Shafi'i, and the Ashab al-Ra'y. This is because it is a contract of exchange, so it is binding, like a sale; and because it is a type of sale, which is only distinguished by a name just as currency exchange (sarf) and advance payment (salam) are distinguished by name. This applies whether he has an excuse or not. This is the view of Malik, al-Shafi'i, and Abu Thawr.