Sahih al-Bukhari 5892
صحيح البخاري#5892SahihNarrated Nafi`:Ibn `Umar said, The Prophet (ﷺ) said, 'Do the opposite of what the pagans do. Keep the beards and cut the moustaches short.' Whenever Ibn `Umar performed the Hajj or `Umra, he used to hold his beard with his hand and cut whatever remained outside his hold
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: 77:109