(2) باب إِحْفَاءِ الشَّارِبِ
It was narrated that Zaid bin Al-Arqam said:
"I heard the Messenger of Allah [SAW] say: 'Whoever does not take from his mustache, he is not one of us.'"
Reference: Sunan an-Nasa'i 5047
In-book reference: Book 48, Hadith 8
English translation: Vol. 6, Book 48, Hadith 5050