(4) باب تَحْرِيمِ الْغَدْرِ
Anas 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.
Reference: Sahih Muslim 1737
In-book reference: Book 32, Hadith 17
USC-MSA web (English) reference(deprecated numbering scheme): Book 19, Hadith 4308