The Holy Quran 9:12 — Surah At-Tawbah

Arabic text

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

Translation

If they break their promises after entering into a treaty and condemn your Deen, then fight the leaders of kufr. Indeed they are such that they have no (regard for the) promises (they make) so that (because of this regard for promises) they (would) refrain (from betraying others).

Tafsir (excerpt) — Tafsir Usmani

Fighting the treacherous disbelievers: that is, if they broke their treaties and pledges (as the Banu Bakr, in violation of the treaty, attacked the Khuza'ah and the Quraysh helped the attackers) and did not desist from disbelief, but went on reviling the true religion and insolently finding fault with it, then know that people of this kind are “ائمۃ الکفر”…

Preview. The full text opens with JavaScript enabled.