Sahih Bukhari Volume 4, Book 52, Hadith Number 279.

Narated By Abu Ishaq : A man asked Al-Bara “O Abu ‘Umara! Did you flee on the day (of the battle) of Hunain?” Al-Bara replied while I was listening, “As for Allah’s Apostle he did not flee on that day. Abu Sufyan bin Al-Harith was holding the reins of his mule and when the pagans attacked him, he dismounted and started saying, ‘I am the Prophet, and there is no lie about it; I am the son of ‘Abdul Muttalib.’ On that day nobody was seen braver than the Prophet.'”