Surah Al-Baqarah, verse 191

وَٱقْتُلُوهُمْ حَيْثُ ثَقِفْتُمُوهُمْ وَأَخْرِجُوهُم مِّنْ حَيْثُ أَخْرَجُوكُمْ ۚ وَٱلْفِتْنَةُ أَشَدُّ مِنَ ٱلْقَتْلِ ۚ وَلَا تُقَـٰتِلُوهُمْ عِندَ ٱلْمَسْجِدِ ٱلْحَرَامِ حَتَّىٰ يُقَـٰتِلُوكُمْ فِيهِ ۖ فَإِن قَـٰتَلُوكُمْ فَٱقْتُلُوهُمْ ۗ كَذَٰلِكَ جَزَآءُ ٱلْكَـٰفِرِينَ ﴿١٩١﴾

2:191 And fight them wherever you find them, and drive them out from where they drove you out, for persecution is far worse than fighting. But do not fight them at the Sacred Mosque unless they fight you there. However, if they fight you, then fight them. Such is the recompense of the disbelievers