The Prophet ﷺ said, "Every traitor will have a banner at his backside on the Day of Resurrection."
حدثنا عفان حدثنا شعبة عن خليد بن جعفر عن أبي نضرة
عن النبي ﷺ قال لكل غادر لواء يوم القيامة عند استه
Its isnad is sahih. Khulayd bin Jafar is truthful, and he has a narration in Muslim. The hadith was narrated by Bukhari 4/127, and Muslim 3/1361, no. 1738, and it has already been mentioned.