obligation of jihād

فَرِحَ ٱلْمُخَلَّفُونَ بِمَقْعَدِهِمْ خِلَـٰفَ رَسُولِ ٱللَّهِ وَكَرِهُوٓا۟ أَن يُجَـٰهِدُوا۟ بِأَمْوَٰلِهِمْ وَأَنفُسِهِمْ فِى سَبِيلِ ٱللَّهِ وَقَالُوا۟ لَا تَنفِرُوا۟ فِى ٱلْحَرِّ ۗ قُلْ نَارُ جَهَنَّمَ أَشَدُّ حَرًّا ۚ لَّوْ كَانُوا۟ يَفْقَهُونَ

Those who remained behind rejoiced in their staying [at home] after [the departure of] the Messenger of Allāh and disliked to strive with their wealth and their lives in the cause of Allāh and said, "Do not go forth in the heat." Say, "The fire of Hell is more intense in heat" - if they would but understand.

وَإِذَآ أُنزِلَتْ سُورَةٌ أَنْ ءَامِنُوا۟ بِٱللَّهِ وَجَـٰهِدُوا۟ مَعَ رَسُولِهِ ٱسْتَـْٔذَنَكَ أُو۟لُوا۟ ٱلطَّوْلِ مِنْهُمْ وَقَالُوا۟ ذَرْنَا نَكُن مَّعَ ٱلْقَـٰعِدِينَ

And when a sūrah was revealed [enjoining them] to believe in Allāh and to fight with His Messenger, those of wealth among them asked your permission [to stay back] and said, "Leave us to be with them who sit [at home]."

۞ إِنَّمَا ٱلسَّبِيلُ عَلَى ٱلَّذِينَ يَسْتَـْٔذِنُونَكَ وَهُمْ أَغْنِيَآءُ ۚ رَضُوا۟ بِأَن يَكُونُوا۟ مَعَ ٱلْخَوَالِفِ وَطَبَعَ ٱللَّهُ عَلَىٰ قُلُوبِهِمْ فَهُمْ لَا يَعْلَمُونَ

The cause [for blame] is only upon those who ask permission of you while they are rich. They are satisfied to be with those who stay behind, and Allāh has sealed over their hearts, so they do not know.