Sahih Bukhari
Good Manners and Form (Al-Adab)
Volume: 008 / Book Number: 073 / Hadith Number: 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.' "