The Messenger of Allah ﷺ said, "When two men make a transaction, each of them has the option to cancel it as long as they have not parted, while they remain together, or until one of them gives the other the choice. If one gives the other the choice and they conclude the sale on that basis, the sale becomes binding. And if they part after having concluded the sale, and neither of them has cancelled it, then the sale has become binding."
حدثنا هاشم حدثنا ليث حدثني نافع
عن رسول الله ﷺ أنه قال إذا تبايع الرجلان فكل واحد منهما بالخيار ما لم يتفرقا فكانا جميعا ويخير أحدهما الآخر فإن خير أحدهما الآخر فتبايعا على ذلك وجب البيع وإن تفرقا بعد أن تبايعا ولم يترك واحد منهما البيع فقد وجب البيع
Its isnad is sahih. Bukhari related it in 4:279 from Qutayba bin Saeed, and Muslim in 1:447 from Qutayba bin Saeed and Muhammad bin Rumh, both of them from Layth bin Saad, with this isnad and similar wording. Something similar in meaning has already passed in abbreviated form at 5130, 5158, and 5418.As for his saying "or he gives choice," in a copy in the margin of K and M it reads "or he gives choice," which agrees with what is in the Sahihayn. And his saying "and if the two of them part after having concluded the sale," and so on, has been dropped from M, which is certainly a scribal oversight, for it is established in H and K and in the Sahihayn.Ibn Kathir mentioned it in 2:413 in abbreviated form, without naming the companion, and then attributed it as "the wording of Bukhari," though there is no basis for singling it out this way, since it is likewise the wording of Muslim.