For you may be sure of this, that everyone who is sexually immoral or impure, or who is covetous (that is, an idolater), has no inheritance in the kingdom of Christ and God.
5. For this ye know. If his readers were at all captivated by the allurements of those vices which have been enumerated, the consequence would be that they would lend a hesitating or careless ear to his admonitions. He determines, therefore, to alarm them by this weighty and dreadful threatening, that such vices shut against us the kingdom of God.
These verses contain a caution against all manner of uncleanness, with proper remedies and arguments proposed: some further cautions are added, and other duties recommended. Filthy lusts must be suppressed, in order to the supporting of holy love. Walk in love, and shun fornication and all uncleanness. Fornication is folly committed between unmarried persons. All uncleanness includes all other sorts of filthy lusts, which were too common among the Gentiles.
Commenting on Ephesians 5:3-20
For this ye know,.... Or, "know ye this", as the Alexandrian copy, and some others, and the Vulgate Latin, Syriac, and Ethiopic versions read: that no whoremonger, nor unclean person; anyone that is guilty of fornication, adultery, incest, &c. Nor covetous man, who is an idolater: as every man is, that indulges his lusts, the idols of his own heart; and who serves divers lusts...