At-Tawbah · 9:81

81. 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.