Abu Dawud Book 19, Hadith Number 3640.
Chapter : Writing the knowledge.
Narated By Zayd ibn Thabit : Al-Muttalib ibn Abdullah ibn Hantab said: Zayd ibn Thabit entered upon Mu’awiyah and asked him about a tradition. He ordered a man to write it. Zayd said: The Apostle of Allah (PBUH) ordered us not to write any of his traditions. So he erased it.