1 Thessalonians 4:5

Lust. Gr. pathos, “emotions,” good or bad, but in the NT only evil desires (Rom. 1:26; Col. 3:5).

Concupiscence. Gr. epithumia, “desire,” “craving,” “longing,” but in the NT generally evil desire, specifically, “lust” (see on Mark 4:19; Rom. 7:7). The phrase “lust of concupiscence” may thus be rendered, “passion of lust.” The close connection between 1 Thess. 4:4 and 5 supports the view that Paul is dealing with sexual aspects of marriage. In v. 4 he makes the positive approach; in v. 5 he stresses the attitude Christians should avoid. Though reared in an immoral atmosphere, they should not allow themselves to be tainted by that immorality.

Gentiles. Or, “heathen.” Since the Thessalonians themselves had been Gentiles, or heathen, they understood Paul’s references. But the fact that the apostle now clearly distinguishes them from the heathen would encourage them to maintain the distinction by refusing to indulge in immorality, as the Gentiles did.

Which know not God. See on Rom. 1:21, 28.