Man, even when saved, has two natures. He retain his sin nature. If he didn't the following statements and commands by Paul would all be moot and useless.
Likewise reckon ye also yourselves to be dead indeed unto sin, but alive unto God through Jesus Christ our Lord. Let not sin therefore reign in your mortal body, that ye should obey it in the lusts thereof. (Romans 6:11-12)
--Why reckon my self to be dead to sin, if I have no sin nature? What a useless command this is.
--Don't let sin reign in your mortal body that you should obey it...
Why? I don't have a sin nature, you say. I wouldn't obey it anyway.
For we know that the law is spiritual: but I am carnal, sold under sin. (Romans 7:14)
--A flat out statement. Paul is carnal. Was he lying?
For that which I do I allow not: for what I would, that do I not; but what I hate, that do I. If then I do that which I would not, I consent unto the law that it is good. (Romans 7:15-16)
--He did things he didn't want to do, and he didn't want to do the things he wanted to do. There was a continual battle going on within him, as there is in you, and in every believer. It is a battle between out two natures--the old vs. the new. What shall I do--Watch the TV vs. read the Bible. (only an example). We face battles every day. How to best use our time; battle of discipline; how not to let Satan get the best of us; how not to let our carnal nature rule over us.
Near the end of this chapter, Paul, in dire desperation cries out:
O wretched man that I am! who shall deliver me from the body of this death? (Romans 7:24)
--He is a wretch, a wicked man. His carnal nature is winning over his new nature. Alas! What to do about it. Then he gives the answer:
I thank God through Jesus Christ our Lord. So then with the mind I myself serve the law of God; but with the flesh the law of sin. (Romans 7:25)
--The battle is in the mind. The victory is in Christ.
With my mind I serve the law of God.
With the flesh I serve the law of sin. The flesh is the carnal nature; that old sin nature that continues to raise its ugly head and causes the believer to backslide. Which one will the believer give into? Will he submit his mind to the Lord Jesus Christ, or allow his flesh to have the better of him? That choice is up to him. He will not lose his salvation. But he can become a carnal and backslidden Christian. The choice is his.
What about the believers that James was writing to? Is it possible for a Christian to actually become an enemy of God? Let's see:
Ye adulterers and adulteresses, know ye not that the friendship of the world is enmity with God? whosoever therefore will be a friend of the world is the enemy of God. (James 4:4)
--God hates the world. If you are friends with the world then you are an enemy of God. You have had an affair. You have committed adultery against God. This is one of the most serious sins a believer can commit, and yet it is rampant in all of our churches--worldly and carnal believers.
They imitate the world.
They imitate the world's dress.
They imitate the world's music.
They imitate the world's amusements.
They "NEED" to have the world's goods.
Love not the world, neither the things that are in the world. If any man love the world, the love of the Father is not in him. For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world. (1 John 2:15-16)
Love not the world.
Be not conformed to the world.
If you are a friend of the world you are an enemy of God. You are a carnal and backslidden Christian.