Charles Ellicott Commentary 1 Thessalonians 4:5

"not in the passion of lust, even as the Gentiles who know not God;" — 1 Thessalonians 4:5 (ASV)

Not in the lust of concupiscence, for such a method of using one’s faculties, such an attempt to acquire mastery of vital powers, is really to abandon them altogether to others. This notion is involved in the very word here translated “lust,” which is more often rendered “passion,” and implies something which befalls a man, something done to him: “Not in the helpless passivity of concupiscence” or uncontrolled desire.

The Gentiles which know not God.—Note the punctuation. The readers of the letter were “Gentiles who knew God.” Their brother Thessalonians are held up to them as melancholy examples of men who are trying in the wrong way to show their power over themselves. Note that this is not one of the crimes which he alleges against Jews.