Sahih Muslim 4536
صحيح مسلم#4536SahihAnas reported Allah's Messenger (ﷺ) having said this:There would be a flag for every perfidious person on the Day of Judgment by which he will be recognised
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 32:17