Sahih al-Bukhari, Hadith 3188 ⓘ
Narrated Ibn `Umar: The Prophet said, "Every betrayer will have a flag which will be fixed on the Day of Resurrection, and the flag's prominence will be made in order to show the betrayal he committed."
حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ، حَدَّثَنَا حَمَّادٌ، عَنْ أَيُّوبَ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ ـ رضى الله عنهما ـ قَالَ سَمِعْتُ النَّبِيَّ صلى الله عليه وسلم يَقُولُ " لِكُلِّ غَادِرٍ لِوَاءٌ يُنْصَبُ لِغَدْرَتِهِ " .
also referenced under: Book 58, Hadith 29 (In-Book) & Volume 4, Book 53, Hadith 411 (USC-MSA)