Surah At-Tawbah — Ayah 81 (9:81)

English translation (Saheeh International)

Those who remained behind¹ 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.

1. - Literally, "were left behind [as Allāh willed]" due to their false excuses having been accepted by the Prophet (ﷺ). While pleased with their assumed deception, in reality, Allāh had prevented their participation knowing of their hypocrisy and evil intent.

Brief commentary

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.