John Calvin Commentary Ephesians 4:20

"But ye did not so learn Christ;" — Ephesians 4:20 (ASV)

But you have not. He now draws a contrast—that of a Christian life—to make it evident how utterly inconsistent it is with the character of a godly person to carelessly defile themselves with the abominations of the Gentiles. Because the Gentiles walk in darkness, they therefore do not distinguish between right and wrong; but those on whom the truth of God shines ought to live in a different manner.

It is not surprising that those for whom the vanity of the senses is a rule of life should yield themselves to base lusts; but the doctrine of Christ teaches us to renounce our natural dispositions. Anyone whose life does not differ from that of unbelievers has learned nothing of Christ, for the knowledge of Christ cannot be separated from the mortification of the flesh.