The people of (the tribe of) Quraiza agreed upon to accept the verdict of Saʿd. The Prophet ﷺ sent for him (Saʿd) and he came. The Prophet ﷺ said (to those people), "Get up for your chief or the best among you!" Saʿd sat beside the Prophet ﷺ and the Prophet ﷺ said (to him), "These people have agreed to accept your verdict." Saʿd said, "So I give my judgment that their warriors should be killed and their women and children should be taken as captives." The Prophet ﷺ said, "You have judged according to the King's (Allah's) judgment." (See Hadith No. 447, Vol. 5)  

أَنَّ أَهْلَ قُرَيْظَةَ نَزَلُوا عَلَى حُكْمِ سَعْدٍ فَأَرْسَلَ النَّبِيُّ ﷺ إِلَيْهِ فَجَاءَ فَقَالَ قُومُوا إِلَى سَيِّدِكُمْ أَوْ قَالَ خَيْرِكُمْ فَقَعَدَ عِنْدَ النَّبِيِّ ﷺ فَقَالَ هَؤُلاَءِ نَزَلُوا عَلَى حُكْمِكَ قَالَ فَإِنِّي أَحْكُمُ أَنْ تُقْتَلَ مُقَاتِلَتُهُمْ وَتُسْبَى ذَرَارِيُّهُمْ فَقَالَ لَقَدْ حَكَمْتَ بِمَا حَكَمَ بِهِ الْمَلِكُ قَالَ أَبُو عَبْدِ اللَّهِ أَفْهَمَنِي بَعْضُ أَصْحَابِي عَنْ أَبِي الْوَلِيدِ مِنْ قَوْلِ أَبِي سَعِيدٍ إِلَى حُكْمِكَ