Obligation of Jihad and striving in the cause of Allah

إِلَّا تَنفِرُوا۟ يُعَذِّبْكُمْ عَذَابًا أَلِيمًا وَيَسْتَبْدِلْ قَوْمًا غَيْرَكُمْ وَلَا تَضُرُّوهُ شَيْـًٔا ۗ وَٱللَّهُ عَلَىٰ كُلِّ شَىْءٍ قَدِيرٌ

If you do not go forth, He will punish you with a painful punishment and will replace you with another people, and you will not harm Him at all. And Allāh is over all things competent.