Al-Matalib al-'Aliyah 4278 — Mention of Quraizah

It is narrated from Sayyiduna Sa'd bin Abi Waqqas (may Allah be pleased with him) that he said that on that day (at the time of the campaign against Banu Qurayzah) Sayyiduna Sa'd bin Mu'adh (may Allah be pleased with him) gave the judgement that every one (of the enemy fighters) over whom the razor had passed should be killed (that is, anyone whose puberty was confirmed by the sign of pubic hair having grown). At this the Messenger of Allah (peace and blessings be upon him) (endorsing and confirming his judgement) said: "You have certainly judged concerning them with the very judgement of Allah Almighty issued from above the seven heavens."
Imam al-Harith recorded it; in its chain, Muhammad bin Umar, Muhammad bin Salih, Sa'd bin Ibrahim and Amir bin Sa'd narrate from his father (Sayyiduna Sa'd bin Abi Waqqas, may Allah be pleased with him).