Surah At-Tawbah — Ayah 42 (9:42)

English translation (Saheeh International)

Had it been a near [i.e., easy] gain and a moderate trip, they [i.e., the hypocrites] would have followed you, but distant to them was the journey. And they will swear by Allāh,¹ "If we were able, we would have gone forth with you," destroying themselves [through false oaths], and Allāh knows that indeed they are liars.

1. - When you return from the Tabūk expedition.

Brief commentary

If the Prophet had called the hypocrites who asked for permission to stay behind to an easy reward and a journey that was not difficult, they would have followed him; but the distance he called them to cover to get to the enemy was too great for them, so they stayed behind. These hypocrites who asked for permission to stay behind would swear by Allah when the Prophet returned to them, saying that if they could have gone out to fight with them they would have done so. They destroy themselves by exposing themselves to Allah’s punishment, because they stayed behind and then swore a lie. Of course, Allah knew they were lying in what they claimed and in what they swore.