Sahih al-Bukhari Book 34, Hadith 66
The Prophet (ﷺ) said, "No deal is settled and finalized unless the buyer and the seller separate, except if
the deal is optional (whereby the validity of the bargain depends on the stipulations agreed upon).
Allah's Messenger (ﷺ) said, "Both the buyer and the seller have the option of canceling or confirming the bargain, as long as they are still together; and unless they separate or one of them gives the other the option of keeping or returning the things and a decision is concluded then, in which case the bargain is considered final. If they separate after the bargain and none of them has rejected it, then the bargain is rendered final."
The Prophet (ﷺ) said, "Both the buyer and the seller have the option of canceling or confirming the bargain unless they separate." The sub-narrator, Hammam said, "I found this in my book: 'Both the buyer and the seller give the option of either confirming or canceling the bargain three times, and if they speak the truth and mention the defects, then their bargain will be blessed, and if they tell lies and conceal the defects, they might gain some financial gain but they will deprive their sale of (Allah's) blessings."