At-Tawbah 9:81

Fariha almukhallafoona bimaqAAadihimkhilafa rasooli Allahi wakarihoo an yujahidoobi-amwalihim waanfusihim fee sabeeli Allahi waqaloola tanfiroo fee alharri qul naru jahannamaashaddu harran law kanoo yafqahoon

Those who remained behind 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.

Those who were left behind were happy with their sitting back to the displeasure of the Messenger of Allah, and they disliked carrying out Jihād in the way of Allah with their wealth and lives, and they said, “Do not march in this hot weather.” Say, “The fire of Jahannam is much more intense in heat,” only if they could understand.