A man came to Bara and asked, "Abu Umarah, did you all turn your backs in flight on the day of Hunayn?"He replied, "I bear witness that the Prophet of Allah ﷺ did not turn his back. Rather, some of the lightly armed and unarmored men among the people rushed forward to engage this clan of Hawazin, who were a people of archers. They shot at them with a volley of arrows like a swarm of locusts, and our men scattered. The enemy then advanced toward the Messenger of Allah ﷺ, while Abu Sufyan bin Harith was leading his mule. He dismounted, prayed, and called for victory, saying, 'I am the Prophet, no lie. I am the son of Abdul-Muttalib. O Allah, send down Your aid.'"Bara said, "By Allah, when the battle grew fierce, we would seek shelter behind him, and the bravest among us was the one who stood level with him," meaning the Prophet ﷺ.
جاء رجل إلى البراء، فقال: أكنتم وليتم يوم حنين يا أبا عمارة؟ فقال: أشهد على نبي الله ﷺ ما ولى، ولكنه انطلق أخفاء من الناس وحسر إلى هذا الحي من هوازن، وهم قوم رماة فرموهم برشق من نبل كأنها رجل من جراد فانكشفوا، فأقبل القوم إلى رسول الله ﷺ، وأبو سفيان بن الحارث يقود به بغلته، فنزل ودعا واستنصر وهو يقول: أنا النبي لا كذب أنا ابن عبد المطلب. اللهم نزل نصرك. قال البراء: كنا والله إذا احمر البأس نتقي به، وإن الشجاع منا للذي يحاذي به يعني ان النبي ﷺ.
Bukhari narrated it in the book of jihad and expeditions (2930) and Muslim in the book of jihad and expeditions (1776: 79), both of them through various routes from Abu Ishaq, who said, and then he related it. The wording given here is Muslim's.