Volume 5 · Book 59 · Hadith 330
Narrated Ibn 'Abbas: The Prophet said on the day (of the battle) of Badr, "This is Gabriel holding the head of his horse and equipped with arms for the battle.
— Sahih Bukhari, Volume 5, Book 59: Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi), Hadith #330