that it is valid for one of them to waive his option in favour of the other.

“And when its period has elapsed, the sale becomes binding.”

The second is for them to stipulate it in the contract for a known period, even if lengthy; its period begins from the time of the contract.

His statement, “And when its period has elapsed, the sale becomes binding”: the author’s wording gives the impression that the option of the sitting has a specified duration which, once it expires, causes it to lapse. However, this is not what the author intended. Rather, he meant when the two parties separate. Had the author said, “And when they separate, the sale becomes binding,” that would have been more appropriate, as it would conform to the hadith: “If they separate after concluding the sale, without either of them having cancelled it, then the sale has become binding” (1).

His statement, “the sale becomes binding,” means that it becomes binding, such that neither party may rescind it except for a valid reason. This matter is agreed upon by scholarly consensus. The basis for this consensus is the Prophet’s statement, peace and blessings be upon him: “Then the sale has become binding.” Here, bindingness applies to both parties: it is binding upon the buyer and upon the seller. From this, we know that a sale is among the binding contracts.

Contracts are of three types:

The first: binding upon both parties.

The second: revocable for both parties.

The third: binding upon one party but not the other.

A contract binding upon both parties cannot be rescinded except with their mutual agreement or for another legal reason, such as a sale and a lease.

A contract revocable for both parties may be rescinded with their mutual agreement or without it, such as agency.