Musannaf Ibn Abi Shayba 27:669

Muhammad ibn Ubayd narrated to us, from Wa'il ibn Dawud, who said: I heard al-Bahiy narrating that Aisha used to say: The Messenger of Allah never sent Zayd ibn Harithah in an army at all, but that he appointed him over them. And had he been alive after him, he would have appointed him as his successor.