Musnad Ahmad 788:268

Yazid narrated to us, he said: Hammad ibn Salamah informed us, from Thabit al-Bunani, from Abu Burdah, from his father, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "If one of you passes through a marketplace, a gathering, or a mosque, and he has arrows with him, let him grasp their heads. Let him grasp their heads." [He said it] three times. Abu Musa said: The affliction did not cease to befall us until some of us struck one another in the faces with them.