Musnad Ahmad 1153:286

Ibn Numayr narrated to us, from Hisham, who said: My father informed me, from Aisha, who said: When the Messenger of Allah (peace and blessings of Allah be upon him) returned from the Trench, and laid down his weapons and bathed, Gabriel (peace be upon him) came to him with dust upon his head. He said: "You have laid down your weapons, but by Allah, I have not laid mine down. Go out to them." The Messenger of Allah (peace and blessings of Allah be upon him) said: "Where?" He said: "Here," and he pointed toward Banu Qurayza. So the Messenger of Allah (peace and blessings of Allah be upon him) went out to them. Hisham said: My father informed me that they surrendered to the judgment of the Messenger of Allah (peace and blessings of Allah be upon him), and he referred the judgment regarding them to Sa'd. He said: "I judge that the fighting men be killed, the women and children be taken captive, and their wealth be divided." Hisham said: My father said: I was informed that the Messenger of Allah (peace and blessings of Allah be upon him) said: "You have judged regarding them with the judgment of Allah, the Almighty and Majestic."