For the good that I want, I do not do,
but I practice the very evil that I do
not want. But if I am doing the very
thing I do not want, I am no longer
the one doing it, but sin which dwells
in me. I find then the principle that
evil is present in me, the one who
wants to do good.
However, you are not in the flesh but
in the Spirit, if indeed the Spirit of God
dwells in you. But if anyone does not
have the Spirit of Christ, he does not
belong to Him. But if the Spirit of Him
who raised Jesus from the dead dwells
in you, He who raised Jesus from the dead
will give life to your mortal bodies
through His Spirit who dwells in you.
So then, brethren, we are under obligation,
not to the flesh, to live according to the
flesh--for if you are living according to
the flesh, you must die; but if by the
Spirit you are putting to death the deeds
of the body, you will live.
To combat indwelling sin we have been given the indwelling Spirit. And it is by the Spirit that we put to death the deeds of the flesh. The frustration in Romans 7 turns into the victory in Romans 8. Yes, the principle of indwelling sin is real, but it is swallowed up by the greater principle of the indwelling Spirit of the victorious Christ.
The issue is not are you struggling with sin, because if you were not a Christian there would be no struggle; but the issue is are you having victory. Too many Christians feel guilty because they struggle with sin, they battle the tempation. These very battles are signs that you indeed have been saved, and now the internal battle between sin and righteousness has begun, because sin does not willingly leave the building, but must be put to death and thrown out.
But take heart, my friends, because greater is He that is in you than he who is in the world, greater is the law of the Spirit of life in Christ Jesus than the law of sin and death, and greater is the indwelling Spirit than indwelling sin. For our great High Priest has been tempted in all things as we are, yet without sin; and now He is able to come to the aid of those who are tempted. The victory over sin is ours in Christ. Don't lose heart in the struggle, but take joy in each victory.