‘Amir bin Sa’d (may Allah have mercy on him) narrates that Sayyiduna Sa’d (may Allah be pleased with him) said: I saw the Messenger of Allah (peace and blessings be upon him) on the day of the Trench laughing so much that his molar teeth became visible. (‘Amir bin Sa’d says) I asked,“Why did the Messenger of Allah (peace and blessings be upon him) laugh so much?”He replied: There was a (disbelieving) man who had a shield, and although Sa’d was a great archer, that disbeliever kept moving his shield here and there to protect his face. Then Sa’d took an arrow from his quiver, and as soon as that disbeliever raised his head, Sa’d immediately shot the arrow, and this time the arrow did not miss but struck him straight on the forehead, and he fell down with his leg raised up. At this, the Messenger of Allah (peace and blessings be upon him) laughed until his blessed teeth became visible. ‘Amir says: I asked,“Why did the Messenger of Allah (peace and blessings be upon him) laugh?”He replied: Because of what Sa’d did to that disbeliever.