Abbas and Abu Sufyan were with him, meaning the Prophet ﷺ. He said, "He addressed them and said, 'Now the battle has grown fierce.'" He also said, "Call out, 'Companions of Surah al-Baqarah!'"
كان عباس وأبو سفيان معه- يعني النبي ﷺ قال: خطبهم وقال: الآن حمي الوطيس وقال: ناد: يا أصحاب سورة البقرة
Ahmad (1772) narrated from Sufyan, who said, "I heard Zuhri once or twice, but I did not memorize it, from Kathir bin Abbas," and he then related it. Its form is that of a mursal narration, for Kathir bin Abbas was not present at that event. However, Muslim narrated it from Ibn Abu Umar, who said, Sufyan bin Uyayna narrated to us, from Zuhri, who said, Kathir bin Abbas informed me, from his father, who said, "I was with the Prophet ﷺ on the day of Hunayn." Muslim said, and he continued the hadith, except that the hadith of Yunus and the hadith of Mamar contain more of it and are more complete.