Musnad Ahmad 730:1

Ibrahim ibn Abi al-Abbas narrated to us, Abd al-Rahman ibn Abi al-Zinad narrated to us, from his father, who said: A man was reported to me who was called Rabi'ah ibn 'Abbad from the Banu al-Dil, and he was a man of the Jahiliyyah (pre-Islamic era), who said: I saw the Prophet, peace and blessings of Allah be upon him, during the Jahiliyyah in the market of Dhu al-Majaz, and he was saying: "O people, say: 'There is no god but Allah,' and you will succeed." The people were gathered around him. Behind him was a man with a bright face, cross-eyed, with two braids, saying: "He is a Sabian, a liar," following him wherever he went. I asked about him, and they mentioned to me the lineage of the Messenger of Allah, peace and blessings of Allah be upon him, and they said to me: "This is his uncle, Abu Lahab."