Musannaf Ibn Abi Shayba 28:1171

Waki’ narrated to us, he said: Sufyan narrated to us, from ‘Abd al-Malik ibn ‘Umayr, he said: I heard ‘Atiyyah al-Qurazi saying: We were presented before the Messenger of Allah (may Allah bless him and grant him peace) on the day of Qurayzah. Whoever had grown pubic hair was killed, and whoever had not grown pubic hair was not killed. I was among those who had not grown pubic hair, so he did not kill me.