Musnad Ahmad 1236:0

Narrated by Tariq ibn Abdullah al-Muharibi: I saw the Messenger of Allah (peace be upon him) in the market of Dhul-Majaz. He was saying: "O people, say: 'There is no god but Allah,' and you will succeed." A man was following him, throwing stones at him and saying: "He is a liar, he is a renegade." I asked: "Who is this?" They said: "This is Muhammad, and he claims he is a Prophet." And they said: "This is his uncle, Abu Lahab." I said: "I am with him." I followed him until he reached the people of Ukaz. He stood among them and said: "O people, say: 'There is no god but Allah,' and you will succeed." A man was following him, throwing stones at him, and his legs were bleeding, and he was saying: "O people, do not obey him, for he is a liar." I asked: "Who is this?" They said: "This is his uncle, Abu Lahab."