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.' " (Using translation from Bukhārī 6177)
عَنِ النَّبِيِّ ﷺ قَالَ الْغَادِرُ يُرْفَعُ لَهُ لِوَاءٌ يَوْمَ الْقِيَامَةِ يُقَالُ هَذِهِ غَدْرَةُ فُلَانِ بْنِ فُلَانٍ