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.
Sahih al-Bukhari Book 8, Hadith 111