From Sahih Bukhari (Hadith 4121):
Narrated Abu Sa`id Al-Khudri:The people of (Banu) Quraiza agreed to accept the verdict of Sa`d bin Mu`adh. So the Prophet (ﷺ) sent for Sa`d, and the latter came (riding) a donkey and when he approached the Mosque, the Prophet (ﷺ) said to the Ansar, "Get up for your chief or for the best among you." Then the Prophet (ﷺ) said (to Sa`d)." These (i.e. Banu Quraiza) have agreed to accept your verdict." Sa`d said, "Kill their (men) warriors and take their offspring as captives, "On that the Prophet (ﷺ) said, "You have judged according to Allah's Judgment," or said, "according to the King's judgment
Reference: Bukhari 4121