Musnad Abu Ya'la al-Mawsili 155:279

Muhammad ibn al-Muthanna narrated to us, Ibn Abi ‘Adi narrated to us, Muhammad ibn ‘Amr narrated to us, from Abu Salamah, from Abu Hurayrah, who said: The Messenger of Allah (ﷺ) went out while the tribe of Aslam were practicing archery. He said: "Shoot, O sons of Ishmael, for your father was an archer. Shoot, and I am with the son of al-Adra'." The people held back their bows and said: "Whoever you are with will be victorious." He said: "Shoot, and I am with all of you."