I was with the Messenger of Allah ﷺ on the day of Hunayn. Abu Sufyan bin Harith bin Abdul-Muttalib and I stayed close to the Messenger of Allah ﷺ and did not leave his side. The Messenger of Allah ﷺ was riding his white mule, which had been gifted to him by Farwa bin Nufatha al-Judhami. When the Muslims and the disbelievers met in battle, the Muslims turned and fled, but the Messenger of Allah ﷺ began urging his mule forward toward the disbelievers.Abbas said, "I was holding the bridle of the mule of the Messenger of Allah ﷺ, restraining it to keep it from going too fast, while Abu Sufyan was holding the stirrup of the Messenger of Allah ﷺ..." The hadith continues at length.
شهدت مع رسول الله ﷺ يوم حنين، فلزمت أنا وأبو سفيان بن الحارث بن عبد المطلب رسول الله ﷺ فلم نفارقه، ورسول الله ﷺ على بغلة له بيضاء، أهداها له فروة بن نفاثة الجذامي، فلما التقى المسلمون والكفار ولى المسلمون مدبرين، فطفق رسول الله ﷺ يركض بغلته قبل الكفار، قال عباس: وأنا آخذ بلجام بغلة رسول الله ﷺ أكفها إرادة أن لا تسرع، وأبو سفيان آخذ بركاب رسول الله ﷺ… الحديث بطوله.
Muslim reported it in the Book of Jihad (1775), from Abu Tahir Ahmad bin Amr bin Sarh, who said, Ibn Wahb told us, Yunus told me, from Ibn Shihab, who said, Kathir bin Abbas bin Abdul-Muttalib told me, who said, Abbas said, and then he related it.