Our bodies are not our natures. Emotions, mind and will are not our natures. When we were in sin we lived in the lusts of our flesh, indulging the desires of the flesh and of the mind. We were, by nature, children of wrath, but because of God's mercy and love, when we were dead in our transgressions, He made us alive together with Christ (Ephesians 1:3-5). Paul goes on to say in Ephesians 2:10, "We are His workmanship..."
The Scripture tells us to put off the old man, and put on the new man. If the old man were the sin nature, we would not be able to put it off, nor could we put on the new man if it were the new nature. The old nature, or sin nature, is only a theory that seemingly allows the believer to live in a condition other than utter dependence on Christ. Because of this, he lives with a battle going on continuously.
I John 1:7 does not teach the need of a continual cleansing from continual sin: "If we continue to sin, we do not know Him." Verses 8 and 10 are not speaking to Christians, but to those who said they had no sin or had not sinned, and had no need of forgiveness. John tells them, in the 9th verse, "If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness." The scripture tells us that He will cleanse us from all unrighteousness, but many have been taught that this doesn't mean what it says.
Many sincere brothers who have been used by God have had little understanding in the area of our personal holiness; thus they have gone off to justify their natural thinking and have come up with many theories which can never bring them to a place of faith. Faith must hear God. When man creates one false theory he usually ends up having to back it up with many other false theories. But the truth sets us free to walk in the Spirit and do His will.
II Peter 1:3 tells us, "His divine power has granted to us everything pertaining to life and godliness." The following verses go on to reveal to us the outworking of our life in God as we "apply all diligence..." This is not a struggle but a rest, a walk in relationship with Christ, as we allow Christ to work in us and through us. It is from our relationship with Him that all the manifestations of His divine nature are revealed in and through us.
Paul said, "I have been crucified with Christ" (that was the old Paul). He went on to say, "...the life which I now live in the flesh (this is the new Paul) I live by faith in the Son of God..." Then he said, "I do not nullify the grace of God; for if righteousness comes through the law, then Christ died needlessly" (Galatians 2:21). We can see that most of the scriptures used to support the two nature theory would put the Christian right back under the law, if viewed in this way.
We need to seek God for understanding, that we might not nullify the grace of God, but be spiritual. We need to stop allowing ourselves to be taught by men with natural minds and natural understanding. This is not possible until we can recognize the word of God flowing through spiritual brethren. "The natural man receiveth not the things of God. He cannot even know God's ways or His working..." (I Corinthians 2:14 RSV).
The salvation that is being preached today allows for sin, but the gospel of the New Testament gives no place for the Christian to practice sin. Man does have a human body, but that is not a sin nature. If it were, we would have to say that Christ had a sin nature because He had a body like ours. But Christ did not have a sin nature. We must conclude that the "nature" is not the body.
Christ also had a mind, emotions, and a will, and they all were set aside for the Father's will to be done through. So we must also conclude that the mind, emotions and will are not a sin nature, in Christ or in us.
Christ had a human nature, but this was not a sin nature. We also have a human nature, and it is not a sin nature. The human nature has only been used to express the sin which was in us because we were sinners. Our bodies and souls controlled us when we were sinners, but if we are in Christ, we are being controlled by the Spirit.
We pray that these truths will set you free from past theories and give you new confidence in your Christian walk.