Sunan an-Nasa'i 5046
سنن النسائي#5046SahihIbn 'Umar said:"The Messenger of Allah [SAW] said: 'Let the beard grow and trim the mustache
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 48:7