Sahih al-Bukhari 6177
صحيح البخاري#6177SahihNarrated Ibn `Umar:The Prophet (ﷺ) said, "For every betrayer (perfidious person), a flag will be raised on the Day of Resurrection, and it will be announced (publicly) 'This is the betrayal (perfidy) of so-and-so, the son of so-and-so
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: 78:201