Musannaf Ibn Abi Shayba 13:3243

Abu Bakr narrated to us, he said: Yazid bin Harun narrated to us, he said: Hisham and Ibn ‘Awn narrated to us, from Ibn Sirin, they both said: He used to say regarding a man who rents a house or a ship, and says: "If I come to you by such-and-such [time], [it is as agreed], otherwise it is yours." He said: If he does not come to him, then it is his.