Ephesians 4:17–24 (NKJV)
17 This I say, therefore, and testify in the Lord, that you should no longer walk as the rest of the Gentiles walk, in the futility of their mind, 18 having their understanding darkened, being alienated from the life of God, because of the ignorance that is in them, because of the blindness of their heart; 19 who, being past feeling, have given themselves over to lewdness, to work all uncleanness with greediness.Ephesians 4:17-24
20 But you have not so learned Christ, 21 if indeed you have heard Him and have been taught by Him, as the truth is in Jesus: 22 that you put off, concerning your former conduct, the old man which grows corrupt according to the deceitful lusts, 23 and be renewed in the spirit of your mind, 24 and that you put on the new man which was created according to God, in true righteousness and holiness.
Paul has told his readers to walk worthy. He has told his readers that God gave gifts to empower them to walk worthy in unity and productivity. He now tells them how not to walk: do not walk as the rest of the Gentiles walk! How do they walk? They walk in futile thinking, darkened reason, and alienated from the life of God. They are ignorant, with blind hearts, past feeling, and participating in lewd lifestyles, unclean and greedy. These attributes point to lives live in opposition to the teaching and examples of Christ first, and also of Paul. Paul tells his disciples to walk worthy, aided by leaders and the precious Holy Spirit, and to avoid the bad habits of other Gentiles who resist Christ and live in their own type of darkness. They are sexually aberrant, crude, and public with their sexual sin. They need redemption and do not know it, and do not want it. They want what they want and give no place to the will of God of the law of God.
Paul reminds them, “you have not so learned Christ.” The converts of Paul, disciples of Christ, know better, and should shun the sinful lifestyles of the loud and ungodly crowd. He calls upon them to put off the old man in its fleshly lusts and be renewed in the spirit of their minds, putting on the new man created by the grace of God through their faith in Him. This new man is righteous and holy, not like the old man, full of deceit and lust. Walk in newness and shun the path of darkness in which you once walked and in which some of your old buddies, pals, and cronies still walk. Be delivered yesterday when you were saved, today as you walk with Christ, and tomorrow as you continue to live in fellowship with the King. In other words, leave that old man alone!