Sunan Ibn Majah 292
سنن ابن ماجه#292SahihIt was narrated that Abu Hurairah said:"The Messenger of Allah said: 'The deeds connected to the Fitrah are five (or five things are connected to the Fitrah): circumcision, shaving the pubic hairs, clipping the nails, plucking the armpit hairs and trimming the mustache
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Fouad Abd al-BaqiSahih
Zubair Ali ZaiSahih - Bukhari And Muslim
In-book reference: 1:26