It was narrated that 'Aishah said:

"Sa'd was wounded on the day of Al-Khandaq [1] when a man of Quraish shot him in the medial arm vein. The Messenger of Allah (ﷺ) pitched a tent (Khaimah) for him in the Masjid so that he could visit him close at hand." [1] Al-Khandaq means the trench. This indicates the battle of the trench which took place during the fifth year after Hijrah.

أَخْبَرَنَا عُبَيْدُ اللَّهِ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ نُمَيْرٍ، قَالَ حَدَّثَنَا هِشَامُ بْنُ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، قَالَتْ أُصِيبَ سَعْدٌ يَوْمَ الْخَنْدَقِ رَمَاهُ رَجُلٌ مِنْ قُرَيْشٍ رَمْيَةً فِي الأَكْحَلِ فَضَرَبَ عَلَيْهِ رَسُولُ اللَّهِ صلى الله عليه وسلم خَيْمَةً فِي الْمَسْجِدِ لِيَعُودَهُ مِنْ قَرِيبٍ ‏.‏