Surah At-Tawbah, Verse 12

وَإِن نَّكَثُوٓاْ أَيۡمَٰنَهُم مِّنۢ بَعۡدِ عَهۡدِهِمۡ وَطَعَنُواْ فِي دِينِكُمۡ فَقَٰتِلُوٓاْ أَئِمَّةَ ٱلۡكُفۡرِ إِنَّهُمۡ لَآ أَيۡمَٰنَ لَهُمۡ لَعَلَّهُمۡ يَنتَهُونَ١٢

wa-in nakathū aymānahum min baʿdi ʿahdihim waṭaʿanū fī dīnikum faqātilū a-immata l-kuf'ri innahum lā aymāna lahum laʿallahum yantahūna

And if they break their oaths after their treaty and defame your religion, then combat the leaders of disbelief, for indeed, there are no oaths [sacred] to them; [fight them that] they might cease.