"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.

أُصِيبَ سَعْدٌ يَوْمَ الْخَنْدَقِ رَمَاهُ رَجُلٌ مِنْ قُرَيْشٍ رَمْيَةً فِي الأَكْحَلِ فَضَرَبَ عَلَيْهِ رَسُولُ اللَّهِ ﷺ خَيْمَةً فِي الْمَسْجِدِ لِيَعُودَهُ مِنْ قَرِيبٍ

When Sa'd b. Mu'adh suffered affliction on the day of Trench (i.e. the battle of Trench) a man shot an arrow in the vein of his hand. The Messenger of Allah ﷺ pitched a tent for him the mosque so that he might visit him from near.

لَمَّا أُصِيبَ سَعْدُ بْنُ مُعَاذٍ يَوْمَ الْخَنْدَقِ رَمَاهُ رَجُلٌ فِي الأَكْحَلِ فَضَرَبَ عَلَيْهِ رَسُولُ اللَّهِ ﷺ خَيْمَةً فِي الْمَسْجِدِ فَيَعُودُهُ مِنْ قَرِيبٍ

Sa'd was wounded on the day of the Battle of the Ditch. A man from the Quraish called Ibn al-Ariqah shot at him an arrow which pierced the artery in the middle of his forearm. The Messenger of Allah ﷺ pitched a tent for him in the mosque and would inquire after him being in close proximity. When he returned from the Ditch and laid down his arms and took a bath, the angel Gabriel appeared to him and he was removing dust from his hair (as if he had just returned from the battle). The latter said: You have laid down arms. By God, we haven't (yet) laid them down. So march against them. The Messenger of Allah ﷺ asked: Where? He pointed to Banu Quraiza. So the Messenger of Allah (may peace he upon him) fought against them. They surrendered at the command of the Messenger of Allah ﷺ, but he referred the decision about them to Sa'd who said: I decide about them that those of them who can fight be killed, their women and children taken prisoners and their properties distributed (among the Muslims). (Using translation from Muslim 1769a)

أُصِيبَ سَعْدٌ يَوْمَ الْخَنْدَقِ رَمَاهُ رَجُلٌ مِنْ قُرَيْشٍ يُقَالُ لَهُ حِبَّانُ بْنُ الْعَرِقَةِ فِي الْأَكْحَلِ فَضَرَبَ عَلَيْهِ رَسُولُ اللهِ ﷺ خَيْمَةً فِي الْمَسْجِدِ لِيَعُودَهُ مِنْ قَرِيبٍ

[Machine] When Sa'd bin Mu'adh was injured on the day of the trench, a man threw a spear at him and the Messenger of Allah, ﷺ , struck a tent in the mosque to provide shade for him until he returned.

لَمَّا أُصِيبَ سَعْدُ بْنِ مُعَاذٍ يَوْمَ الْخَنْدَقِ رَمَاهُ رَجُلٌ فِي الْأَكْحَلِ فَضَرَبَ عَلَيْهِ رَسُولُ اللهِ ﷺ خَيْمَةً فِي الْمَسْجِدِ لِيَعُودَهُ مِنْ قَرِيبٍ