Quran 9:12 At-Tawbah, ayah 12 of 129

وَإِن نَّكَثُوٓا۟ أَيْمَـٰنَهُم مِّنۢ بَعْدِ عَهْدِهِمْ وَطَعَنُوا۟ فِى دِينِكُمْ فَقَـٰتِلُوٓا۟ أَئِمَّةَ ٱلْكُفْرِ ۙ إِنَّهُمْ لَآ أَيْمَـٰنَ لَهُمْ لَعَلَّهُمْ يَنتَهُونَ ۝١٢

9:12 And if they break their pledges after their treaty (hath been made with you) and assail your religion, then fight the heads of disbelief - Lo! they have no binding oaths - in order that they may desist.