Musannaf Ibn Abi Shayba 16:322

Abu Bakr narrated to us, he said: Hafs narrated to us, from Isma'il bin Abi Khalid, from his father, who said: I entered upon a man while he was eating dates and drinking milk. He said: "Come, and say the name of Allah (Bismillah), for the Messenger of Allah, may Allah bless him and grant him peace, used to call them 'the two best things' (al-atyabayn)."