﴿ فَرِحَ ٱلْمُخَلَّفُونَ بِمَقْعَدِهِمْ خِلَٰفَ رَسُولِ ٱللَّهِ وَكَرِهُوٓا۟ أَن يُجَٰهِدُوا۟ بِأَمْوَٰلِهِمْ وَأَنفُسِهِمْ فِى سَبِيلِ ٱللَّهِ وَقَالُوا۟ لَا تَنفِرُوا۟ فِى ٱلْحَرِّ ۗ قُلْ نَارُ جَهَنَّمَ أَشَدُّ حَرًّۭا ۚ لَّوْ كَانُوا۟ يَفْقَهُونَ ﴾

“THOSE [hypocrites] who were left behind rejoiced in their staying away [from war] after [the departure of] God's Apostle, for they hated the thought of striving with their possessions and their lives in God's cause; and they had [even] said [to the others], "Do not go forth to war in this heat!" Say: "The fire of hell is hotter by far!" Had they but grasped this truth!”

Please check ayah 9:82 for complete tafsir.