Hadith: The saying of the Prophet (may Allah's peace and blessings be upon him) on the day (of the battle) of Badr: This is Jibrīl holding the head of his horse and equipped with the tools of war

عن ابن عباس رضي الله عنهما أن النبي صلى الله عليه وسلم قال يوم بدر: «هذا جبريلُ، آخذٌ برأس فَرَسِه، عليه أَدَاةُ الحَرْب».
[صحيح] - [رواه البخاري]

Ibn ‘Abbās (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) on the day (of the battle) of Badr, said: "This is Jibrīl holding the head of his horse and equipped with tools of war."
[Authentic hadith] - [Narrated by Bukhari]

Explanation

This Hadīth is about the participation of angels, headed by Jibrīl (peace be upon him) in the battle of Badr. The Prophet (may Allah's peace and blessings be upon him) informed that he saw Jibrīl mounting his horse in the battle of Badr, while equipped with tools of war to fight alongside the believers, to support and consolidate the Prophet (may Allah's peace and blessings be upon him) and to back his Companions.