From Sahih Bukhari (Hadith 463):
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's wound was bleeding profusely and Sa`d died in his tent
Reference: Bukhari 463