Quran At-Tawbah 9:123
يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُواْ قَٰتِلُواْ ٱلَّذِينَ يَلُونَكُم مِّنَ ٱلۡكُفَّارِ وَلۡيَجِدُواْ فِيكُمۡ غِلۡظَةٗۚ وَٱعۡلَمُوٓاْ أَنَّ ٱللَّهَ مَعَ ٱلۡمُتَّقِينَ ١٢٣
Translation
O you who have believed, fight against those adjacent to you of the disbelievers and let them find in you harshness. And know that Allāh is with the righteous.