Musannaf Ibn Abi Shayba 36:460

Muhammad ibn Fudayl narrated to us, from Ash'ath, from al-Hakam ibn Utaybah, who said: When the people fled from the Prophet, may Allah bless him and grant him peace, on the day of Hunayn, the Prophet, may Allah bless him and grant him peace, began to say: "I am the Prophet, there is no lie; I am the son of Abd al-Muttalib." He said: There remained with him only four people—three from Banu Hashim and one man from others: Ali ibn Abi Talib and al-Abbas, and they were in front of him; and Abu Sufyan ibn al-Harith, holding the rein; and Ibn Mas'ud on his left side. He said: No one approached toward him except that he was killed, and the polytheists were around him, fallen.