Aamir bin Sa'd (may Allah be pleased with him) says, My father Sa'd said, "Messenger of Allah ﷺ laughed on the day of the Battle of Khandaq till his teeth showed." Aamir (may Allah be pleased with him) says, "I asked why did he laugh?" he replied, "A Kaafir had a shield, and Sa'd was a great archer. The kaafir protected himself by swaying the shield from side to side covering his forehead. (Sayyidina Sa'd (may Allah be pleased with him) was a famous marksman, but the kaafir did not let the arrows get him). Sa'd (may Allah be pleased with him) took an arrow (and kept it ready in the bow). When the non believer removed the shield from his head, he quickly aimed at the kaafir and did not miss the target, i.e. the (enemy's) forehead. The enemy immediately fell down, his legs rising into the air. On that Messenger of Allah ﷺ laughed till his mabaraak teeth showed." I asked, "Why did Messenger of Allah ﷺ laugh?" He replied, "Because of what Sa'd had done to the man."

حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، قَالَ: حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللهِ الأَنْصَارِيُّ، قَالَ: حَدَّثَنَا عَبْدُ اللهِ بْنُ عَوْنٍ، عَنْ مُحَمَّدِ بْنِ مُحَمَّدِ بْنِ الأَسْوَدِ، عَنْ عَامِرِ بْنِ سَعْدٍ، قَالَ: قَالَ سَعْدٌ: لَقَدْ رَأَيْتُ النَّبِيَّ ﷺ، ضَحِكَ يَوْمَ الْخَنْدَقِ حَتَّى بَدَتْ نَوَاجِذُهُ قَالَ: قُلْتُ: كَيْفَ كَانَ؟ قَالَ: كَانَ رَجُلٌ مَعَهُ تُرْسٌ، وَكَانَ سَعْدٌ رَامِيًا، وَكَانَ يَقُولُ كَذَا وَكَذَا بِالتُّرْسِ يُغَطِّي جَبْهَتَهُ، فَنَزَعَ لَهُ سَعْدٌ بِسَهْمٍ، فَلَمَّا رَفَعَ رَأْسَهُ رَمَاهُ فَلَمْ يُخْطِئْ هَذِهِ مِنْهُ يَعْنِي جَبْهَتَهُ وَانْقَلَبَ الرَّجُلُ، وَشَالَ بِرِجْلِهِ: فَضَحِكَ النَّبِيُّ ﷺ حَتَّى بَدَتْ نَوَاجِذُهُ قَالَ: قُلْتُ: مِنْ أَيِّ شَيْءٍ ضَحِكَ؟ قَالَ: مِنْ فِعْلِهِ بِالرَّجُلِ.