What is the relationship between the old nature and the new nature in a believer?
The old nature and new nature are contrary forces that declare war on each other from the moment of salvation. The old nature, aligned with Satan and rebellion, opposes the new nature, which follows God's righteousness and holiness. This produces a constant warfare within every believer until death or the Rapture.
Les teaches that the old nature actually declares war on the new nature, and consequently the new nature must declare war on the old nature, so it is a constant battle. The battle lines are defined from the very moment a person is saved until they leave this life, either by death or by the Rapture; until then, there is constant warfare. He identifies the conflict as the old Adam, or the flesh, warring against the Spirit, while the Holy Spirit wars against the flesh, or old Adam. These two forces within each and every believer are contrary and at total odds; they cannot agree on anything. The new nature has a whole new set of values in compliance with the righteousness, holiness, and laws of God, whereas the old nature, whose God is Satan, the god of this world, is bent in rebellion and unbelief. They are two totally opposite forces that war constantly, so you cannot do the things that you would.
More Questions
Why is the Christian life a constant battle between the old and new nature?
The old nature declares war on the new nature, and consequently the new nature declares war on the old nature, so the Christian life is a constant battle.