Musnad Ahmad 8:181

Rawh narrated to us, Ibn ‘Awn narrated to us, from Muhammad ibn Muhammad ibn al-Aswad, from ‘Amir ibn Sa’d, from his father, who said: "On the day of the Trench, there was a man shielding himself, and he began moving the shield like this, placing it above his nose, then he would say: 'Like this,' and lower it afterward. He said: So I reached for my quiver and took out a feathered arrow from it, and I placed it on the notch of the bow. When he said: 'Like this,' and lowered the shield, I shot. I have not forgotten the sound of the arrow striking such and such a part of the shield. He said: And he fell, and he kicked with his leg. The Prophet of Allah, peace and blessings of Allah be upon him, laughed—I think he said: until his molars appeared. He said: I asked: 'Why?' He said: 'Because of what the man did.'"