Ayesha reported,

Saad was wounded on the day of the Battle of the Trench. A man from Quraysh called Hibban bin Araqah shot him, striking him in the median vein of his arm. The Prophet 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, he laid down his weapons and bathed. Then Jibreel came to him while he was shaking the dust from his head and said, "You have laid down your weapons? By Allah, I have not laid mine down. Go out to them."The Prophet ﷺ asked, "Where to?"Jibreel pointed toward Banu Qurayzah. The Messenger of Allah ﷺ went to them, and they surrendered, agreeing to abide by his judgment. He referred the judgment to Saad, who said, "I judge concerning them that the fighting men be killed, the women and children taken captive, and their wealth be divided." The hadith continues at length.

عن عائشة قالت

أصيب سعد يوم الخندق، رماه رجل من قريش، يقال له حبان بن العرقة، رماه في الأكحل، فضرب النبي ﷺ خيمة في المسجد ليعوده من قريب، فلما رجع رسول الله ﷺ من الخندق وضع السلاح واغتسل، فأتاه جبريل عليه السلام وهو ينفض رأسه من الغبار، فقال: وضعت السلاح، والله ما وضعته، اخرج إليهم. قال النبي ﷺ: فأين؟ فأشار إلى بني قريظة، فأتاهم رسول الله ﷺ فنزلوا على حكمه، فرد الحكم إلى سعد، قال: فإني أحكم فيهم: أن تقتل المقاتلة، وأن تسبى النساء والذرية، وأن تقسم أموالهم… الحديث بطوله.