أَخْبَرَنَا عَلِيُّ بْنُ حُجْرٍ، قَالَ أَنْبَأَنَا عَبِيدَةُ بْنُ حُمَيْدٍ، عَنْ يُوسُفَ بْنِ صُهَيْبٍ، عَنْ حَبِيبِ بْنِ يَسَارٍ، عَنْ زَيْدِ بْنِ أَرْقَمَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنْ لَمْ يَأْخُذْ شَارِبَهُ فَلَيْسَ مِنَّا " .
It was narrated that Zaid bin Arqam said: "The Messenger of Allah (PBUH) said: 'Whoever does not trim his mustache, he is not from one of us.'" Translation Not Available
Book Ref: Sunan An Nisai Book 1 Hadith 13
Web Ref: Sunan An Nisai Vol 1 Book 1 Hadith 13