What is the meaning of "unless it is an option transaction, and it is not permissible for him to leave his companion for fear that he will ask him to annul the sale," as stated in the Hadith, "The two parties to a sale have the option [to annul it] until they separate, unless it is an option transaction, and it is not permissible for him to leave his companion for fear that he will ask him to annul the sale," with illustrative examples?

The option of the session (khiyar al-majlis) is established according to the majority of scholars, unless the two parties agree that there is no option between them, and that the sale is binding immediately upon the contract without separation. The hadith mentioned in the question was narrated by Ahmad, Abu Dawud, and Al-Tirmidhi, who graded it hasan, and Al-Nawawi authenticated it.

His saying: "unless it is a transaction with an option" (إلا أن تكون صفقة خيار) bears two possible meanings: 1. A sale in which the option (khiyar) is stipulated, so it does not become binding upon their separation, nor is their separation the end limit for the option in it. 2. A sale in which they stipulated that there should be no option between them, so it becomes binding immediately upon the contract without separation. This is the interpretation favored by Al-Shawkani.

His saying: "and it is not lawful for him to rush his companion in disposing of it for fear that he might ask for annulment" (ولا يحل له أن يبادر صاحبه بالتصرف خشية أن يستقيله) has been interpreted differently. The intended meaning is for fear that his companion might annul the sale while still in the session. Others have interpreted the negation of lawfulness as signifying disliking (karahah), and "yastaqeelah" (أن يستقيله) has been interpreted as annulment (faskh).