If the sale was with an option, then the sale is binding." Agreed upon (18). Taking the addition is more appropriate. Mutual waiving [al-takhayur] at the beginning of the contract and after it within the session are the same. Mutual waiving at its beginning is for one to say: "I have sold to you, and there is no option between us," and the other accepts it on that basis; thus, there is no option for them. Mutual waiving after it (19) is for each of them to say after the contract: "I have chosen to finalize the contract," or "to make it binding," or "I have chosen the contract," or "I have dropped my option." The contract then becomes binding on both parties. If one of them chooses [to waive] and the other does not, it becomes binding on him alone, just as if the condition of an option were for both, and one of them dropped his option while the other did not. The companions of al-Shafi'i said: There are two views regarding mutual waiving at the beginning of the contract. The more manifest of them is that the option is not terminated, because it is the dropping of a right before its cause, and thus it is not permissible, like the option of pre-emption [shuf'a]. Based on this, is the contract voided by this condition? There are two perspectives based on [the ruling regarding] invalid conditions. Our position is his statement (peace and blessings of Allah be upon him): "If one of them gives the other the choice, and they sell upon that, the sale is then binding." And his statement: "Unless the sale was with an option; if the sale was with an option, then (20) the sale is binding" (21). This is explicit regarding the ruling, so that which contradicts it is not to be relied upon. Also, because what affects the option [while sitting] in the session also affects it when occurring concurrently with the contract, such as stipulating an option. Furthermore, it is one of the two options in a sale, so it is permissible to divest it, like the option of condition. Their statement that it is the dropping of an option before its cause is not so; the cause of the option is the absolute sale, whereas a sale with mutual waiving is not a cause for it.