فَرِحَ ٱلۡمُخَلَّفُونَ بِمَقۡعَدِهِمۡ خِلَٰفَ رَسُولِ ٱللَّهِ وَكَرِهُوٓاْ أَن يُجَٰهِدُواْ بِأَمۡوَٰلِهِمۡ وَأَنفُسِهِمۡ فِي سَبِيلِ ٱللَّهِ وَقَالُواْ لَا تَنفِرُواْ فِي ٱلۡحَرِّۗ قُلۡ نَارُ جَهَنَّمَ أَشَدُّ حَرّٗاۚ لَّوۡ كَانُواْ يَفۡقَهُونَ

Farihal mukhallafoona bimaq'adihim khilaafa Rasoolil laahi wa karihooo ai yujaahidoo bi amwaalihim wa anfusihim fee sabeelil laahi wa qaaloo laa tanfiroo fil harr; qul Naaru jahannama ashaddu harraa; law kaanoo yafqahoon

Those who were left behind (in the Tabuk expedition) rejoiced in their inaction behind the back of the Messenger of Allah: they hated to strive and fight, with their goods and their persons, in the cause of Allah: they said, "Go not forth in the heat." Say, "The fire of Hell is fiercer in heat." If only they could understand!

— At-Taubah (ٱلتَّوْبَة), 9:81