Characteristic terms. The old man and the new man are two orders of manhood. The characteristics of the old man are seen looking at the whole race of Adam; morally depraved. The characteristics of the new man are seen in the life of Jesus. Note: we don’t see all the features of the old man in Adam personally, or any one sinner, but we see them in aggregate looking at the whole race of Adam. On the other hand, we see all the features of the new man in the life of Christ personally! Eph. 4:22 gives the characteristics of the old man, and Eph. 4:24 gives the characteristics of the new man.
The old man is an abstract term that describes the characteristic features of the fallen race of Adam in its depraved moral character. It “corrupts itself according to the deceitful lusts” (Eph. 4:22). The Old Man does not have the power, knowing good and evil, to choose the good. The test for Adam was a test of obedience, would he remain upright? He failed the test and proved himself unrighteous. But by eating of the tree he gained knowledge. It was by gaining knowledge that Adam fell, because he did not have the power, knowing good and evil, to choose the good. In order to choose the good there must be divine life (to want it) and divine power (to act). The “old man” is the state of knowing good and evil and of descending into corruption by the power of lust. That order of manhood “corrupts itself”… it consistently chooses the evil. That state (our former “conversation”) doesn’t characterize us any more! Three different Greek words are used:
Each time the old man is mentioned, the associated verb is increasing in force. The “crucifixion” of our old man was accomplished at the cross, it took place 2000 years ago. The “putting off” of our old man was accomplished when we believed the gospel and were sealed with the Holy Spirit of promise. But in every case it is past tense (KJV translation is misleading)… our old man has been put off. The scripture never exhorts a Christian to “put off” the old man, because that already happened when we got saved. However, there is a corresponding lifestyle that mirrors the old man, and those things we are told to put off: “But now, put off, ye also, all these things, wrath, anger, malice, blasphemy, vile language out of your mouth.” (Col. 3:8).
The new man is an abstract term that describes the characteristic features of those “in Christ”. We are “created in truthful righteousness and holiness” (Eph. 4:24). That means that when we were sealed with the Spirit, we were brought into a new creation race, and as such we are blessed far beyond Adam even if he had never sinned! We now have (1) a holy nature and (2) divine power… this is a new character of manhood. We know good and evil, and we chose the good and hate the evil!
Just like with the old man, each time the new man is mentioned it is in the past tense (KJV translation is misleading)… the new man has been put on. The scripture never exhorts a Christian to “put on” the new man, because that already happened when we got saved. We have put on the new man in that “if any man be in Christ, he is a new creature!” However, there is a corresponding lifestyle that mirrors the new man, and those things we are told to put on: “Put on therefore, as the elect of God, holy and beloved, bowels of compassion, kindness, lowliness, meekness, longsuffering.” (Col. 3:12).
Difference between Old/New Nature and Old/New Man. Very often the term “old man” is used interchangeably with the old nature, and likewise the term “new man” is used interchangeably with the new nature. In a certain sense, the old man may be inclusive of the flesh, because the old man “character” is the outward manifestation of the old nature. The same can be said for the new nature. However, strictly speaking, scripture indicates that the old and new man are distinct from the two natures. The old man is “put off”… but how would you put off a nature? You can’t. We always have the flesh in us until the rapture (or death), but we have “crucified the flesh” (Gal. 5:24) and need to keep it in that place of death. The same follows with the new nature. We can’t put on a new nature; we must have one imparted to us. The concept of “putting off” and “putting on” is appropriate for a character, which is what the old and new man are.
“The terms “old man” and “new man” are very definitely used in scripture. I judge that neither term can be used of an individual as such. That is, an individual could not say, “I am the old man;” nor, “I am the new.” The terms are generic and comprehensive, embracing – the first — all that we were “in Adam;” and the second — all that believers are “in Christ.” Nor do I find that scripture will allow us to say that we have the “old man” in us — while it teaches most fully, that we have “the flesh” in us to the end.” (Romans 7:25).” – F.G. Patterson, A Chosen Vessel, p.51
Often great Bible teachers would use these terms interchangeably, but on certain occasions they would make the distinction clear. For example, J. N. Darby made the distinction in his letter to J. B. Stoney in 1875, while at the same time revealing that the common “habit” among believers is to use the term “old man” when referring of the flesh.
Difference between the old man and the first man. The “old man” is not to be confused with the “first man“, which denotes a different aspect of the human race under Adam. The old man denotes the corruption of the race, whereas the first man denotes what is natural, earthy, and soulish in the race, compared to the second man who is Christ; heavenly and spiritual. For example, you wouldn’t say bringing in musical instruments to the remembrance of the Lord was the “old man”, but you would say it was the “first man”. The first man was tested up to the cross, proven bankrupt, but never said to be judged by God. The old man however, is said to be crucified or condemned (Rom. 6:6).