I have heard this discussion most of my life. There are two natures Flesh, and Spirit, "Natural man and Saved Man" what ever you call them they DO NOT exist in a person at the same time. Paul was clear in Rom. 8:2
For the law of the Spirit of life in Christ Jesus has set you free from the law of sin and of death.
Rom 8:5 For those who are according to the flesh set their minds on the things of the flesh, but those who are according to the Spirit, the things of the Spirit.
When we are saved the old is passed away all things become new, God said "I will not remember, I will set the past as far away as east from west"
WE are new creatures in Christ, Priest of God. Yet, every knows without me saying we still struggle to be good servants of God, We are not without problems that we must deal with, But, Praise God we have an intercessor before God for us.
Rom 8:34 who is the one who condemns? Christ Jesus is He who died, yes, rather who was raised, who is at the right hand of God, who also intercedes for us.
The discussion of two natures and we never truly get past the sin nature comes from several views of Total Depravity.
IMO we were made free moral agents with a free will and are morally responsible for all we do. We were made for fellowship with God, To Rule the creation of God, and to know HIM. There is no place for total depravity in understanding the bible.
There are always two groups, In CHRIST in the Spirit, Serving God, or In the FLESH
Rom 1:22 Professing to be wise, they became fools,
Rom 1:23 and exchanged the glory of the incorruptible God for an image in the form of corruptible man and of birds and four-footed animals and crawling creatures.
Rom 1:24 Therefore God gave them over in the lusts of their hearts to impurity, so that their bodies would be dishonored among them.
Rom 1:25 For they exchanged the truth of God for a lie, and worshiped and served the creature rather than the Creator, who is blessed forever. Amen.
THERE HAS ALWAYS BEEN TWO GROUPS IT SHOULD NOT BE SO HARD TO SEE!!