Sunan an-Nasa'i 9
سنن النسائي#9Sahihأَخْبَرَنَا الْحَارِثُ بْنُ مِسْكِينٍ، قِرَاءَةً عَلَيْهِ وَأَنَا أَسْمَعُ، عَنِ ابْنِ وَهْبٍ، عَنْ يُونُسَ، عَنِ ابْنِ شِهَابٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، عَنْ أَبِي هُرَيْرَةَ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم قَالَ " الْفِطْرَةُ خَمْسٌ الاِخْتِتَانُ وَالاِسْتِحْدَادُ وَقَصُّ الشَّارِبِ وَتَقْلِيمُ الأَظْفَارِ وَنَتْفُ الإِبْطِ " .
It was narrated from Abu Hurairah that the Messenger of Allah (ﷺ) said:"The Fitrah are five: Circumcision, removing the pubes, trimming the mustache, clipping the nails, and plucking the armpit hairs
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 1:9