John Chrysostom

"For we hear of some that walk among you disorderly, that work not at all, but are busybodies." This indeed he says here; but there, in the first Epistle, he says, "that ye may walk honestly towards them that are without." On what account? Perhaps there was as yet no such thing. …

Homily on 2 Thessalonians 5 ↗

Theophylact of Ohrid

Since our mind is in constant motion, when we do not occupy it with needful matters, it gives itself over to unseemly matters, as was said above, and begins to busy itself with prying into how others live, and from there passes into gossip, idle talk, and empty chatter. Therefore, one ought to labor, working with one's own hands. He who has the strength to work but gives himself over to idleness should not even ask for alms. You will say: I pray and I fast. But that is not the work of the hands. …

Commentary on 2 Thessalonians ↗

Thomas Aquinas

Then when he says "for we have heard," he says why this precept is necessary, for the Apostle says this not so much on the basis of a duty to teach as because of the people's fault. And so first, he sets out the sin that makes the precept necessary; second, he applies a remedy, at "now we charge." He says, therefore, "for we have heard," as though to say: the reason I do not hide this precept is that "we have heard there are some among you who walk disorderly, working not at all." For a man's soul must always be occupied with …

Commentary on 2 Thessalonians ↗