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 who remained behind rejoiced in their staying [at home] after [the departure of] the Messenger of Allah and disliked to strive with their wealth and their lives in the cause of Allah and said, "Do not go forth in the heat." Say, "The fire of Hell is more intensive in heat" - if they would but understand.
Those hypocrites who failed to join the battle of Tabūk were happy not to strive in Allah’s path, in opposition to the Messenger of Allah. They were reluctant to strive with their wealth and live in Allah’s path as the believers did. They said to their fellow hypocrites, in order to keep them behind, ‘Do not march in the heat!’ The battle of Tabūk was during the hot season. Say to them, O Messenger: The fire of Hell that awaits the hypocrites is much hotter than this heat that they are running away from, if they only knew.