Old Nature and New Nature Encyclopedia

The terms. The old nature and the new nature are terms that are not found verbatim in the Word of God, but what they represent is found many times. For example, the old nature is called “the mind of the flesh”, or “sin”, or “the law of sin”, or “sin that dwells in me.” The new nature is called “the inner (or, inward) man”, or “the law of my mind”.
 
The old nature is the nature that we were born with, which wants to sin.
  • It is totally depraved and cannot be improved“Because the mind of the flesh is enmity against God: for it is not subject to the law of God; for neither indeed can it be.” (Rom. 8:7). Also, “the flesh profits nothing” (John 6:63). 
  • It is the weakness of the law… if you try to impose a list of rules on the flesh, it will flare up worse than ever: “For what the law could not do, in that it was weak through the flesh…” (Rom 8:3a). See also Rom. 7:7-9. 
  • God has condemned it“…God, having sent his own Son, in likeness of flesh of sin, and for sin, has condemned sin in the flesh” (Rom. 8:3b).

The new nature is the nature we get when we are quickened or “born again”. It desires to please God.

  • It wants to please God“For I delight in the law of God according to the inward man” (Rom. 7:22).
  • The believer identifies with it. The man in Rom. 7 stops identifying his personality with the old nature, and begins identifying with the new nature, calling it “I”. This indicates a progress in his understanding.
  • It doesn’t have the power to act on its good desires. Hence the powerless feeling of the man in Rom. 7 who wants to please God but doesn’t have the strength.

The war. In Rom. 7 the man learns of these two natures. His conclusion is that the old nature is fighting his new nature, and that the old nature wins every time.

“I see another law in my members (old nature), warring in opposition to the law of my mind (new nature), and bringing me into captivity to the law of sin (old nature) which exists in my members.” (Rom. 7:23)
The desire to please God (new nature) is only half the solution. He needs power to walk (the indwelling Spirit) to get deliverance from the old sinful nature. Just as a car engine requires gasoline to perform, so the new nature needs the power of the Spirit to perform.
 
Confusion between Old/New Nature and Old/New Man. Very often the old nature is confused with the old man, and likewise the new nature is confused with the new man. Scripture is very clear on this. The old man is “put off”… but how would you put off a nature? You can’t. We always have the flesh 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 
Deliverance Equations. Understanding the old and new natures is important in order for us to have deliverance from sin. We see this in Romans 7 where the narrator describes a struggle he went through before he obtained deliverance. Part of that process was understanding that he had two natures, and that the problem lay with the old nature (the flesh). The new nature had right desires, but no power. He needed a power outside of himself (the Spirit) to deliver him. The following equations are a helpful way to see it:
 
Strength
of the
Flesh
> 
Strength
of the
New nature
 
Strength
of the
Flesh
<<
Strength
of the
Spirit
 
New
Nature
(desire)
+ 
Indwelling
Spirit
(power)
=
Deliverance from
the Flesh
(performance)
 
Summarizing Chart. The roll of the old and new natures in deliverance as well as the old and new man are shown below in a summarizing chart.