Romans 7 shows the two conflicts that are going on in a believer. One is not real them ( not their true nature ). The flesh even though it stems from the corrupted Adamic influence in the world is now not the real us.
The flesh and the law of sin in our body - it wages war against the real us in Christ.
The flesh is ways to think and act that "were" the manner of living we had when we were in Adam but now are left over the old man died on the cross with Christ. ( Eph 4:22 - in reference to your former manner of living )
Romans 7:17-18 (NASB)
[SUP]17 [/SUP] So now, no longer am I ( the new man ) the one doing it, but sin which dwells in me (in my body which has the flesh with the power of sin in it ).
[SUP]18[/SUP] For I know that nothing good dwells in me (my body which has the flesh in it ), that is, in my flesh; for the willing is present in me ( in my new man ), but the doing of the good is not.
Romans 7:20-23 (NASB)
[SUP]20 [/SUP] But if I am doing the very thing I ( new man) do not want, I ( new man ) am no longer the one doing it, but sin which dwells in me ( in the flesh).
[SUP]21[/SUP] I find then the principle that evil is present in me (new man ), the one who wants to do good.
[SUP]22 [/SUP] For I joyfully concur with the law of God in the inner man, ( new man),
[SUP]23 [/SUP] but I see a different law in the members of my body, waging war against the law of my mind and making me a prisoner of the law of sin which is in my members.
italics = my words
Then Romans chapter 8 comes in and shows us how to walk according to the Spirit and not the flesh to put to death the deeds of the body ( flesh in the body ). Rom 8:13
We are not fighting a civil war within ourselves ( the flesh and the law of sin do not belong to our new nature which in Christ. ). Jesus said " A house divided will not stand."
We do not have "2 selves" we have the true self in Christ and we still have the flesh. Even though the flesh manifests "itself" with "its" lusts through our bodies - it is not the real us in Christ.
We are still responsible for the deeds done in the body as they will affect our life here on this earth and we are to yield our members to the righteousness that is in us in Christ.
Sin is destructive and will destroy us and those around us if we don't walk by the Spirit - our true selves in Christ because Christ is joined to our spirit and His life will bear fruit on us the branches. The Holy sSirit transforms us as we behold the glory of the Lord as in a mirror.
We have such a great salvation in our Lord Jesus Christ! Let's keep our eyes on the Lord and not the circumstances of life. Peter walking on the water is a prefect picture of the true Christian life.