There dwells in the believer both sin and Christ

"For I know that nothing good dwells in me, that is, in my flesh. For I have the desire to do what is right, but not the ability to carry it out. For I do not do the good I want, but the evil I do not want is what I keep on doing.

Now if I do what I do not want, it is no longer I who do it, but sin that dwells within me."

"I have been crucified with Christ. It is no longer I who live, but Christ who lives in me."

"Do you not believe that I am in the Father and the Father is in me? The words that I say to you I do not speak on my own authority, but the Father who dwells in me does his works."

"You, however, are not in the flesh but in the Spirit, if in fact the Spirit of God dwells in you. Anyone who does not have the Spirit of Christ does not belong to him. But if Christ is in you, although the body is dead because of sin, the Spirit is life because of righteousness. If the Spirit of him who raised Jesus from the dead dwells in you, he who raised Christ Jesus from the dead will also give life to your mortal bodies through his Spirit who dwells in you."

"For the desires of the flesh are against the Spirit, and the desires of the Spirit are against the flesh, for these are opposed to each other, to keep you from doing the things you want to do."

"Beloved, I urge you as sojourners and exiles to abstain from the passions of the flesh, which wage war against your soul."

There dwells in the believer both sin and the Spirit of Jesus Christ. There is a war going on. The believer himself has been crucified. The believer himself no longer lives, but it is either sin that will live, or Christ that will live in the believer. The believer's heart has been changed, that now the believer does not want to sin, but wants to do righteousness. Yet the ability to do good is absent in the believer. It is the Holy Spirit, who dwells in the believer and does the good through the believer.

The believer therefore must live fully dependent on God, that God enable him to do those things that he wants to do. If God gives not the strength, the man can only do those things that he does not want to do. Prayer is therefore the natural progression of those who have the desire but not the ability to do the good that they so long to do:

Lord, deliver us from the body of death, and let us live for you. Send forth Your Holy Spirit to us! Help us by the Spirit to do those things that we want to do!

"Likewise the Spirit helps us in our weakness. For we do not know what to pray for as we ought, but the Spirit himself intercedes for us with groanings too deep for words. And he who searches hearts knows what is the mind of the Spirit, because the Spirit intercedes for the saints according to the will of God."