Key verse: 24
A FEW RULES FOR CHRISTIAN BEHAVIOR
In this passage and the following, Paul focuses on the Christians in pagan churches, showing them the path to take after conversion.
1. The old man (17-22)
Up to now, the pagans had lived the only way they knew, as described in verses 17-19. Yet, after conversion, they gave up their bad habits and adopted new behavior which affected their personality and life. The apostle stands his ground concerning the main cause for idolatry and excess living that disfigured greco-roman life in the first century. It was, in sum, the vanity of their intelligence, and it had two consequences. A man non-renewed was darkened in his understanding of spiritual reality. He suffered due to separation from God, being guilty of ignoring and refusing to submit to Him. Such resistance inevitably leads to numbness and insensitivity towards God, what Paul calls "hardness of heart" (18).
2. The new man (23-24)
Because of Jesus, the pagans now shed their old nature. The call to shed the old man like we shed clothing may seem to be an act of despair, since the fallen creature finds himself in a desperate situation. Yet, Paul addresses Christians for whom the renewing of the spirit, started during conversion, is a continuous experience. Grace, like nature, detests emptiness. Quiting bad habits does not suffice. We must also be clothed with the new man, given during the new birth through the Holy Spirit. This second nature must dominate more and more a Christian's moral life, helping him to triumph over his internal struggles. Regeneration and control through the Spirit restore the image of God which had been shattered by sin. The corrupted man who has now been redeemed by Christ and transformed by the Spirit finds again what he had lost in Adam: justice (being right before the Creator) and holiness (the condition necessary for communing with a holy God). Both are required by the truth of God.