The Messenger of Allah ﷺ said, "Every traitor will have a banner on the Day of Resurrection, raised for him in proportion to his treachery. Indeed, there is no traitor more grievous than a ruler who betrays his people."
قال رسول الله ﷺ: لكل غادر لواء يوم القيامة، يرفع له بقدر غدره، ألا ولا غادر أعظم من أمير عامة.
Muslim narrated it in jihad and expeditions (1738:16), from Zuhayr bin Harb, who said, Abdul-Samad bin Abdul-Warith narrated to us, who said, Mustamirr bin Rayyan narrated to us, from Abu Nadra, from Abu Saeed, and he related it.