Sahih al-Bukhari 8:111
Narrated `Aisha:
On the day of Al-Khandaq (battle of the Trench' the medial arm vein of Sa`d bin Mu`ad was injured and the Prophet (ﷺ) pitched a tent in the mosque to look after him. There was another tent for Banu Ghaffar in the mosque and the blood started flowing from Sa`d's tent to the tent of Bani Ghaffar. They shouted, "O occupants of the tent! What is coming from you to us?" They found that Sa`d' wound was bleeding profusely and Sa`d died in his tent.
Reference
Sahih al-Bukhari 8:111
In-book reference
Book 8, Hadith 111
Arabic Text
حَدَّثَنَا زَكَرِيَّاءُ بْنُ يَحْيَى، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ نُمَيْرٍ، قَالَ حَدَّثَنَا هِشَامٌ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، قَالَتْ أُصِيبَ سَعْدٌ يَوْمَ الْخَنْدَقِ فِي الأَكْحَلِ، فَضَرَبَ النَّبِيُّ صلى الله عليه وسلم خَيْمَةً فِي الْمَسْجِدِ لِيَعُودَهُ مِنْ قَرِيبٍ، فَلَمْ يَرُعْهُمْ ـ وَفِي الْمَسْجِدِ خَيْمَةٌ مِنْ بَنِي غِفَارٍ ـ إِلاَّ الدَّمُ يَسِيلُ إِلَيْهِمْ فَقَالُوا يَا أَهْلَ الْخَيْمَةِ، مَا هَذَا الَّذِي يَأْتِينَا مِنْ قِبَلِكُمْ فَإِذَا سَعْدٌ يَغْذُو جُرْحُهُ دَمًا، فَمَاتَ فِيهَا.