Commentary
The details given in the verse tell us that there were two kinds of people among the Bedouins of the desert. First, there were those who visited the Holy Prophet ﷺ and requested that they might be excused from Jihad and allowed to stay behind. Then, there were the arrogant and rebellious among them who did not even bother to take the trouble of excusing themselves out of it. They just stayed behind.
When the Holy Prophet ﷺ allowed Jadd ibn Qays that he may not go on Jihad,' says Sayyidna Jabir ibn ` Abdullah ؓ ، ` some hypocrites also came to him, offered their excuses and sought his permission to stay out of Jihad. As for the permission, he let them have it, but he did realize that they were making false excuses, therefore, he turned away from them. Thereupon, this verse was revealed.'
It made it clear that their excuse was unacceptable. Therefore, they were served with the warning of a painful punishment. However, by saying: اَلَّذِینَ کَفَرُوا مِنھُم (those of them who disbelieve), a hint was given that the excuse given by some of them was not because of their disbelief or hypocrisy, rather, it was because of their natural laziness. So, they were not to be affected by the punishment to fall upon those disbelievers.