Narrated Atiyyah al-Qurazi:

I was among the captives of Banu Qurayzah. They (the Companions) examined us, and those who had begun to grow hair (pubes) were killed, and those who had not were not killed. I was among those who had not grown hair.

حَدَّثَنَا مُحَمَّدُ بْنُ كَثِيرٍ، أَخْبَرَنَا سُفْيَانُ، أَخْبَرَنَا عَبْدُ الْمَلِكِ بْنُ عُمَيْرٍ، حَدَّثَنِي عَطِيَّةُ الْقُرَظِيُّ، قَالَ كُنْتُ مِنْ سَبْىِ بَنِي قُرَيْظَةَ فَكَانُوا يَنْظُرُونَ فَمَنْ أَنْبَتَ الشَّعْرَ قُتِلَ وَمَنْ لَمْ يُنْبِتْ لَمْ يُقْتَلْ فَكُنْتُ فِيمَنْ لَمْ يُنْبِتْ ‏.‏