Musannaf Ibn Abi Shayba 27:438

Abdullah ibn Numayr narrated to us, from Musa al-Juhani, who said: Fatima, daughter of Ali, narrated to me, saying: Asma, daughter of Umays, narrated to me, saying: I heard the Messenger of Allah, may Allah bless him and grant him peace, say to Ali: "You are to me in the position of Aaron to Moses, except that there is no prophet after me."