Ayesha reported,

Saad was wounded on the day of the Battle of the Trench. A man from Quraysh called Ibn al-Arqah shot him with an arrow that struck him in the median vein of his arm. The Messenger of Allah ﷺ pitched a tent for him in the mosque so he could visit him from nearby.When the Messenger of Allah ﷺ returned from the Trench and laid down his weapons, he bathed. Then Jibreel came to him while he was shaking the dust from his head and said, "Have you laid down your weapons? By Allah, we have not laid them down. Go out against them."The Messenger of Allah ﷺ asked, "Where?"Jibreel pointed toward Banu Qurayzah. So the Messenger of Allah ﷺ fought them, and they surrendered to the judgment of the Messenger of Allah ﷺ. The Messenger of Allah ﷺ referred the judgment concerning them to Saad.Saad said, "I judge that the fighting men among them be killed, that the children and women be taken captive, and that their wealth be divided."

عن عائشة قالت

أصيب سعد يوم الخندق رماه رجل من قريش يقال له: ابن العرقة رماه في الأكحل، فضرب عليه رسول الله ﷺ خيمة في المسجد يعوده من قريب، فلما رجع رسول الله ﷺ من الخندق وضع السلاح، فاغتسل، فأتاه جبريل، وهو ينفض رأسه من الغبار، فقال: وضعت السلاح؟ والله ما وضعناه، اخرج إليهم. فقال رسول الله ﷺ: فأين؟ فأشار إلى بني قريظة، فقاتلهم رسول الله ﷺ فنزلوا على حكم رسول الله ﷺ، فرد رسول الله ﷺ الحكم فيهم إلى سعد، قال: فإني أحكم فيهم أن تقتل المقاتلة، وأن تسبى الذرية، والنساء، وتقسم أموالهم.