The people of Quraiza surrendered accepting the decision of Sa'd b. Mu'adh about them. Accordingly, the Messenger of Allah (ﷺ) sent for Sa'd who came to him riding a donkey. When he approached the mosque, the Messenger of Allah (ﷺ) said to the Ansar: Stand up to receive your chieftain. Then he said (to Sa'd): These people have surrendered accepting your decision. He (Sa'd) said: You will kill their fighters and capture their women and children. (Hearing this), the Propbot (may peace he tpon him) said: You have adjudged by the command of God. The narrator is reported to have said: Perhaps he said: You have adjuged by the decision of a king. Ibn Muthanna (in his version of the tradition) has not mentioned the alternative words.

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).