What did the Prophet Muhammad (saw) say about buyers and sellers having the option to cancel or confirm a bargain before they separate?
 Narrated Ibn `Umar:                     The Prophet said, "The buyer and the seller have the option to cancel or confirm the bargain before they separate from each other or if the sale is optional." Nafi` said, "Ibn `Umar used to separate quickly from the seller if he had bought a thing which he liked."