Hypocrites stay behind
They think the enemy has not withdrawn. If the enemy were to return, they would wish to be far away in the desert, merely hearing news of the battle rather than fighting in it. Even if they were among you, they would barely participate.
33:20They hold that the clans have not retired (for good); and if the clans should advance (again), they would fain be in the desert with the wandering Arabs, asking for the news of you; and if they were among you, they would not give battle, save a little.