The Messenger of Allah ﷺ said, "The extremists are doomed." He said it three times.
قال رسول الله ﷺ: هلك المتنطعون قالها ثلاثا.
Muslim narrated it in "Knowledge" (2670) via Ibn Jurayj, from Sulayman bin Atiq, from Talq bin Habib, from Ahnaf bin Qays, from Abdullah, and he mentioned it.