The people of Qurayza agreed to surrender on the condition that Saad bin Muaz would decide their fate. The Prophet ﷺ sent for Saad, who came riding on a donkey. When he drew near the mosque, the Prophet ﷺ said to the Ansar, "Stand up for your leader," or "for the best among you."Then he said, "These people have submitted to your judgment."Saad said, "Their fighters shall be killed and their women and children taken captive."The Prophet ﷺ said, "You have judged according to the ruling of Allah," and sometimes he said, "according to the ruling of the King."
نزل أهل قريظة على حكم سعد بن معاذ، فأرسل النبي ﷺ إلى سعد فأتى على حمار، فلما دنا من المسجد قال للأنصار: قوموا إلى سيدكم أو خيركم فقال: هؤلاء نزلوا على حكمك، فقال: تقتل مقاتلتهم، وتسبي ذراريهم، قال: قضيت بحكم الله، وربما قال: بحكم الملك.
Bukhari reported it in the chapter on military expeditions (4121), and Muslim in the chapter on jihad and military expeditions (64:1768), both from Muhammad bin Bashshar, who said, Ghundar (that is, Muhammad bin Jafar) narrated to us, Shuba bin Hajjaj narrated to us, from Saad bin Ibrahim, who said, I heard Abu Umama say, I heard Abu Saeed Khudri say, and then he related it.As for what Hakim reported (2/123-124), and from him Bayhaqi in his Kubra (9/63), from the hadith of Muhammad bin Salih Tammar Madini, from Saad bin Ibrahim, from Amir bin Saad bin Abu Waqqas, that Saad bin Muaz passed judgment on Banu Qurayza, and then related the hadith, in which it says, "Today he has judged concerning them with the judgment of Allah, which He judged from above the heavens," this is defective, for Muhammad bin Salih Tammar contradicted Shuba bin Hajjaj, the well-known imam, and his contradiction is not accepted. Abu Hatim pointed this out in his Ilal (971), as did Bukhari in Tarikh al-Kabir (4/291), and Daraqutni in his Ilal (573).