Musnad Imam Shafi'i

It is narrated from Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (ﷺ) said: "Each of the buyer and the seller has the option (to cancel the transaction) as long as they have not separated from each other, except in the case of a sale with a stipulated option (i.e., a sale in which the option has already been stipulated beforehand)." Imam Shafi'i (may Allah have mercy on him) said that Ibn Umar (may Allah be pleased with them both), who heard this from the Prophet (ﷺ), when he would buy something and wanted to finalize the sale, he would separate from his companion and walk a little, then return (thus the sale would be finalized).

It is also narrated from Ibn Umar (may Allah be pleased with them both) through another chain of transmission.

It is narrated from Abdullah bin Umar (may Allah be pleased with them) that the Messenger of Allah (peace be upon him) said: "The buyer and the seller both have the option (to cancel the transaction) as long as they have not separated from each other, except in the case of a sale with a stipulated option."

Ibn Umar (may Allah be pleased with them both) narrated that the Messenger of Allah (ﷺ) said: "When two parties engage in a sale, each of them has the option (to cancel or confirm the sale) as long as they have not separated, or unless they have chosen the option of finalizing the sale." Nafi' said that when Ibn Umar (may Allah be pleased with them both) would make a sale and wanted to finalize it, he would walk a little away from that place and then return.

Hakim bin Hizam (may Allah be pleased with him) narrated that the Messenger of Allah (ﷺ) said: "The buyer and the seller have the option (to cancel the transaction) as long as they have not separated. If they both speak the truth and do not conceal any defect, then blessing is decreed for their transaction. But if they lie and conceal defects, the blessing is erased from their transaction."

Abu Al-Wadi narrated that we were in a battle when one of our companions sold a horse to a man. When we intended to depart, he brought the dispute to Abu Barzah (may Allah be pleased with him). So Abu Barzah (may Allah be pleased with him) said: I heard the Messenger of Allah (ﷺ) say, "The two parties involved in a sale have the option (to cancel or confirm the sale) until they separate."

Abdullah bin Tawus narrates from his father that he said: The Messenger of Allah ﷺ gave a man the option after a sale (had become effective), so that man said: May Allah grant you a long life, who are you? The Messenger of Allah ﷺ replied: "A man from the Quraysh." Abdullah said: My father used to swear that there is an option after a sale (has become effective).