Musnad Ahmad 730:2

Surayj narrated to us, Ibn Abi al-Zinad narrated to us, from his father, from Rabi'ah ibn 'Abbad al-Du'ali—and he was a man of the Jahiliyyah who then accepted Islam—he said: I saw the Messenger of Allah, peace and blessings of Allah be upon him—and he mentioned the hadith—he said: So I said: "Who is this?" They said: "This is Muhammad ibn 'Abdullah ibn 'Abd al-Muttalib, and he is mentioning Prophethood." I said: "Who is this who is calling him a liar?" They said: "This is his uncle, Abu Lahab." Abu al-Zinad said: So I said to Rabi'ah ibn 'Abbad: "You were young on that day." He said: "No, by Allah, I was of sound mind on that day; I was carrying the water skin," meaning I was carrying it.