Sahih al-Bukhari 5893
صحيح البخاري#5893SahihNarrated Ibn `Umar:Allah's Messenger (ﷺ) said, "Cut the moustaches short and leave the beard (as it is)
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 77:110