Hadith: I witnessed the Day of Hunayn with the Messenger of Allah (may Allah's peace and blessings be upon him). Abu Sufyān ibn al-Hārith ibn ‘Abd al-Muttalib and I stuck with the Messenger of Allah (may Allah's peace and blessings be upon him) and we did not leave him. The Messenger of Allah (may Allah's peace and blessings be upon him) was riding on his white mule

عن أبي الفضل العباس بن عبد المطلب رضي الله عنه قال: شهدت مع رسول الله صلى الله عليه وسلم يوم حُنَيْنٍ، فلَزِمْتُ أنا وأبو سفيان بن الحارث بن عبد المطلب رسول الله صلى الله عليه وسلم فلم نفارقه، ورسول الله صلى الله عليه وسلم على بَغْلَةٍ له بيضاء، فلما التقى المسلمون والمشركون وَلَّى المسلمون مدبرين، فطَفِقَ رسول الله صلى الله عليه وسلم يَرْكُضُ بَغْلَتَهُ قِبَلَ الكفار، وأنا آخِذٌ بلِجامِ بَغْلَةِ رسول الله صلى الله عليه وسلم أَكُفُّها إِرَادَةَ أن لا تُسرع، وأبو سفيان آخِذٌ برِكاب رسول الله صلى الله عليه وسلم فقال رسول الله صلى الله عليه وسلم : «أي عباس، نادِ أصحاب السَّمُرَةِ». قال العباس - وكان رجلا صَيِّتًا - فقلت بأعلى صوتي: أين أصحاب السَّمُرَةِ، فوالله لكأن عَطْفَتَهُم حين سمعوا صوتي عَطْفَةَ البقر على أولادها، فقالوا: يا لبيك يا لبيك، فاقتتلوا هم والكفار، والدعوةُ في الأنصار يقولون: يا معشر الأنصار، يا معشر الأنصار، ثم قُصِرَتِ الدعوة على بني الحارث بن الخَزْرَجِ، فنظر رسول الله صلى الله عليه وسلم وهو على بغلته كالمتطاول عليها إلى قتالهم، فقال: «هذا حِينَ حَمِيَ الوَطِيسُ»، ثم أخذ رسول الله صلى الله عليه وسلم حَصَيَاتٍ فرمى بهن وجوه الكفار، ثم قال: «انْهَزَمُوا ورَبَّ مُحَمَّدٍ»، فذهبت أنظر فإذا القتال على هيئته فيما أرى، فوالله ما هو إلا أن رماهم بحَصياته، فما زِلْت أرى حَدَّهُم كَلِيلًا وأمرَهم مُدبرًا.
[صحيح] - [رواه مسلم]

Abu al-Fadl Al-‘Abbās ibn ‘Abd al-Muttalib (may Allah be pleased with him) reported: I witnessed the Day of Hunayn with the Messenger of Allah (may Allah's peace and blessings be upon him). Abu Sufyān ibn al-Hārith ibn ‘Abd al-Muttalib and I stuck with the Messenger of Allah (may Allah's peace and blessings be upon him) and we did not leave him. The Messenger of Allah (may Allah's peace and blessings be upon him) was riding on his white mule. When the Muslims met the disbelievers on the battlefield, the Muslims retreated, but the Messenger of Allah (may Allah's peace and blessings be upon him) began to spur his mule on towards the disbelievers. I was holding onto the Messenger’s mule’s bridle (may Allah's peace and blessings be upon him) restraining it from going very fast. Abu Sufyān who was holding the Messenger’s mule’s stirrup (may Allah's peace and blessings be upon him) said: "O Al-‘Abbās, call out to the people of Samurah." Al-‘Abbās (who was a man with a loud voice) called out at the top of his voice: "Where are the people of Samurah?" Al-‘Abbās said: "And by Allah, when they heard my voice, they came back (to us) as cows come back to their calves, and they said: 'We are here, we are here!'" Al-‘Abbās said: “They began to fight the disbelievers. Then there was a call to the Ansār. Those (who called out to them) shouted: ‘O you people of the Ansār!' O people of the Ansār!‘ Banu al-Hārith ibn al-Khazraj were the last to be called. The Messenger of Allah (may Allah's peace and blessings be upon him) who was riding on his mule watched at their fight, stretched his neck forward, and said: ‘This is the time when the fight is raging hot.' Then the Messenger of Allah (may Allah's peace and blessings be upon him) took (some) pebbles and threw them in the faces of the disbelievers and said: ‘By the Lord of Muhammad, they are defeated.'" Al-‘Abbās said: “I went round and saw that the battle was in the same condition that I had seen it. And, by Allah! It remained in that same condition until he threw the pebbles. I continued to watch until I saw that their force had faded and they began to retreat."
[Authentic hadith] - [Narrated by Muslim]

Explanation

Abu al-Fadl al-‘Abbās ibn ‘Abd al-Muttalib (may Allah be pleased with him) reported that he witnessed the battle of Hunayn with the Messenger of Allah (may Allah's peace and blessings be upon him). When the Muslims and the disbelievers met and fought vigorously, some of the Muslims fled. So, the Messenger of Allah (may Allah's peace and blessings be upon him) spurred his mule toward the disbelievers, but Al-‘Abbās was holding the bridle, restraining it from rushing toward the enemy, and Abu Sufyān was holding the Prophet's stirrup. The Prophet (may Allah's peace and blessings be upon him) asked Al-‘Abbās to call the People of the Samurah; the people who had given the Prophet, may Allah's peace and blessings be upon him the pledge of allegiance under a tree called Samurah on the Day of Hudaybiyah, in the sixth year after Hijrah. Al-‘Abbās, who was endowed with a loud voice, called to the people of Samurah, as if reminding them not to forget their pledge to the Prophet (may Allah's peace and blessings be upon him) under that tree. When they heard the call, they returned quickly, as if they were a herd of cattle coming back to their absent calves. They said in one voice that they were there, ready to fight. So, the Muslims and the disbelievers fought. The Ansār were called later and then Banu al-Hārith; a big tribe from the Khazraj, were the only tribe left to be called. The Prophet (may Allah's peace and blessings be upon him) watched the fight from on top of his mule and said that it was the time for the fighting to become fierce. He then took some pebbles and threw them in the faces of the disbelievers and said optimistically, or by way of an announcement, that the disbelievers were defeated, swearing by the Lord of Muhammad. Al-‘Abbās went to check this out and found the fighting still going on, but when the Prophet (may Allah's peace and blessings be upon him) threw the pebbles the disbelievers began to grow weak and disgraced.