Sin is a choice that we make to disobey God and do what we know to be wrong. We cannot as children of God be forced to sin we have to choose to sin. I agree that the affects of the fall in a physical sense will be with us until death but sin is not a physical entity that we can hold and see and study. We can see the results of sin and the fruit of sin and the acting out of sin but not the principle of sin itself. Ageing, death, disease and sickness are all things that we see they are all physical but there is no sin in experencing any of these things. By the very fact that we overcome sin by walking in the spirit shows it to be a spiritual battle conquered by spiritual means.
Romans 8:2 For the law of the Spirit of life in Christ Jesus hath made me free from the law of sin and death.
1 Thessalonians 5:23 And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and
body be preserved blameless unto the coming of our Lord Jesus Christ.
I agree that one can be free in spirit but not in spirit or in other words they can be saved and not have the fallen carnal nature eradicated they are simply not sanctified wholly yet.
Romans 8:10 And if Christ be in you, the
body is dead because of sin; but the Spirit is life because of righteousness.
11 But if the Spirit of him that raised up Jesus from the dead dwell in you, he that raised up Christ from the dead
shall also quicken your mortal bodies by his Spirit that dwelleth in you.