Al Fath Ayah 16

قُل لِّلْمُخَلَّفِينَ مِنَ ٱلْأَعْرَابِ سَتُدْعَوْنَ إِلَىٰ قَوْمٍ أُوْلِى بَأْسٍ شَدِيدٍ تُقَـٰتِلُونَهُمْ أَوْ يُسْلِمُونَ‌ۖ فَإِن تُطِيعُواْ يُؤْتِكُمُ ٱللَّهُ أَجْرًا حَسَنًا‌ۖ وَإِن تَتَوَلَّوْاْ كَمَا تَوَلَّيْتُم مِّن قَبْلُ يُعَذِّبْكُمْ عَذَابًا أَلِيمًا ١٦ Say to nomadic Arabs, who stayed behind, “You will be called ?to fight? against a people of great might, who you will fight unless they submit. If you then obey, Allah will grant you a fine reward. But if you turn away as you did before, He will inflict upon you a painful punishment.”