Narrated Abu Hurairah:
that the Messenger of Allah (ﷺ) said: "Five are from the Fitrah: Cutting the pubic hair, circumcision, paring the mustache, plucking the under arm hair and trimming the fingernails." (JA)
English reference (JA): Vol. 5, Book 41, Hadith 2756 (JA)
Arabic reference (JA): Book 43, Hadith 2981 (JA)