Romans 7:14-25

For we know that the law is spiritual, but I am carnal, sold under sin.  For what I am doing, I do not understand. For what I will to do, that I do not practice; but what I hate, that I do.  If, then, I do what I will not to do, I agree with the law that it is good.  But now, it is no longer I who do it, but sin that dwells in me. For I know that in me (that is, in my flesh) nothing good dwells; for to will is present with me, but how to perform what is good I do not find. For the good that I will to do, I do not do; but the evil I will not to do, that I practice. Now if I do what I will not to do, it is no longer I who do it, but sin that dwells in me.

 I find then a law, that evil is present with me, the one who wills to do good. For I delight in the law of God according to the inward man. But I see another law in my members, warring against the law of my mind, and bringing me into captivity to the law of sin which is in my members.  O wretched man that I am! Who will deliver me from this body of death? I thank God—through Jesus Christ our Lord!

So then, with the mind I myself serve the law of God, but with the flesh the law of sin.

Our natures are imbedded with sin.  Like our DNA which pre-determines our physical appearance and make-up; so our nature is of sinful composition.  We receive the word of God; but then find ourselves at war.  The sinful nature warring against the spiritual nature.  What a place to be!  There is a principle at work here.  What we focus on gains supremacy and drives our being.  When we focus on the things that comprise the natural, the sinful nature is at the forefront of our awareness.  When we focus on the spiritual, the sinful nature must take the back seat.  In Christ, we are set free of this sin-bondage.  In Christ means focused upon Him, covered by Him, aware of our place in Him and what we do is drawn from Him.