Musnad Ahmad 938:4

Abu Ahmad narrated to us, Kathir bin Zayd narrated to us, from al-Muttalib bin Abdullah, who said: Zayd bin Thabit entered upon Mu'awiyah and narrated a hadith to him. Mu'awiyah ordered a person to write it down. Zayd said: "The Messenger of Allah (peace and blessings of Allah be upon him) forbade us from writing down anything of his hadith," so he erased it.