Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: When we used to make a transaction with each other, both parties had the option (to cancel), as long as the two parties involved in the transaction had not separated from each other. Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: Once, I and Sayyiduna Uthman made a transaction; I sold my land, which was in the valley, for his land, which was in Khaybar. Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) says: When I sold it to him, after that I quickly turned back on my steps, fearing that before we separated, Sayyiduna Uthman might cancel the transaction.