Good Manners and Form (Al-Adab)

Bukhari :: Book 8 :: Volume 73 :: Hadith 196

Narrated Ibn 'Umar:

The Prophet 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.' "