Notice another interesting similarity in terminology whenever Paul speaks of the new man. Quite consistently, he uses the verb "to put on." The Greek verb is enduo, which means, literally, "to sink into." By extension, it means "to enter into," "to get into," or "to put on" (Vine's Expository Dictionary of New Testament Words). New Testament writers often use it when referring to putting on clothes (see Matthew 6:25; 27:31; Mark 1:6; I Thessalonians 5:8; Revelation 1:13; 15:6; etc.).
Paul repeatedly uses the metaphor of putting on clothes when he commands us to adopt the Christian way of life. With the same predictability, he speaks of taking clothes off to describe the abandonment of this world's lifestyle. We see it again in Colossians 3:9-10, where he speaks of our "put[ting] off the old man with his deeds" and our "put[ting] on the new man." He uses the same figure of speech in Ephesians 4:22-24. In Ephesians 6:11-17, the apostle goes a step further when he tells us how to dress the new man: "Put on the whole armor of God."
God's consistent use of the analogy of donning clothes to describe our adoption of the new man tells us a lot about the choices we must make daily. The logical conclusion of the metaphor is as inescapable as it is meaningful: The clothing we wear is largely a matter of our choice. Unless an adult is in very special circumstances, as in prison or the military, he has wide discretion in the matter of clothing. His is the choice of what to wear and when to wear it. He determines when to take clothes off and when to put them on. More than this, it is a choice he makes daily—sometimes many times a day—as he determines what to wear in different social contexts.
So it is with the Christian walk, the way of life of the new man. Daily, repeatedly each day, we must choose to "put on" the Christian way of life.
That is what Paul is telling us through his splendid clothing analogy: Christianity is a way of life. We must choose to put on that way of life—and to keep it on. Just as we do with a well-worn garment, we must come to feel so at home with the new man—so comfortable with his way of life—that we absolutely refuse to take it off for any reason at all.
In addition, God's consistent use of the clothing analogy argues against the Protestants' false doctrine of eternal security. "Once saved, always saved" is the cry of some Protestants. Others put it in a slightly different way: "It was all done at the cross."
What is wrong with this? "Born-again" Protestants, so-called Christians who claim the new man was born in them when they "accepted" Christ, have in fact abdicated virtually all personal responsibility for their salvation! Take their thought to its logical conclusion: When we were physically born, from our viewpoint, it just happened—we had no say about it at all! It was out of our control. So, the "born-again" Christian believes that he "accepts Christ," and, presto, he is saved, forever born as a spirit being, a new man. Thus, now, in this life, he has no further responsibility. Christ did it all "at the cross" and must, upon his confession of faith, irrevocably save him.
This false doctrine permits its adherents to evade all responsibility to choose daily to follow Christ. True Christians know, because of the clothing analogy, that they have that ongoing responsibility to "put on the new man."
In describing the new man, the birth or conception analogy is conspicuous by its absence. However, by its repeated presence, the clothing analogy is equally conspicuous.