Musnad Ahmad 788:104

'Abd al-Rahman ibn Mahdi narrated to us, Sufyan narrated to us, from Abu Ishaq, from al-Aswad, who said: Abu Musa said: "I came to the Messenger of Allah, may Allah bless him and grant him peace, while I was of the opinion that 'Abd Allah was from the people of the house," or whatever he mentioned of that.