The Book of Adornment
48/1. Chapter:
The Fitrah
Sunan an-Nasai
أَخْبَرَنَا قُتَيْبَةُ، عَنْ مَالِكٍ، عَنِ الْمَقْبُرِيِّ، عَنْ أَبِي هُرَيْرَةَ، قَالَ خَمْسٌ مِنَ الْفِطْرَةِ تَقْلِيمُ الأَظْفَارِ وَقَصُّ الشَّارِبِ وَنَتْفُ الإِبْطِ وَحَلْقُ الْعَانَةِ وَالْخِتَانُ .
It was narrated that Abu Hurairah said: "Five things are of the Fitrah: Clipping the nails, trimming the mustache, plucking the armpit hairs, shaving the pubes, and circumcision." (Sahih Mawquf)
Reference : Sunan an-Nasa'i 5044In-book reference : Book 48, Hadith 5English translation : Vol. 6, Book 48, Hadith 5047