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. (ESV)
Let's have a frank discussion. You and I have a problem. The problem is our flesh is completely corrupt. What makes it worse is that we rarely acknowledge just how bad this problem is. One of the greatest hindrances to living a godly life is believing the false notion that our flesh isn't really that bad after all.
Paul helps us to understand just how bad the problem is. There is nothing good in our flesh. Did you catch that? Nothing. That word in the original language means, "nothing." How often have we made the assumption that we are not so bad after all, and then we fall headlong into some prevailing sin. What happened? We underestimated the sinfulness of our flesh.
Paul presents a conundrum for us. We have the desire to do what is right, but not the ability. My wife sometimes reminds me that I should be quiet. I remind her that I have the desire to be quiet, but not the ability. All silliness aside, this is a problem for all of us. Our regenerated spirit wants to please the savior, but our flesh hinders that ability.
The Puritans had a term that should be re-introduced to our modern Christian understanding. They talked about the "mortification of the flesh." We need to daily put to death the flesh which only wants to destroy us. Colossians 3:1-17 is a great place to go to learn more about this idea of putting away the flesh and being clothed with Christ.
Our flesh is corrupt. If you are not doing anything to put the flesh to death you will not be able to do the good that you desire to do for Christ Jesus. Take a few moments and read Colossians 3:1-17. Mortify the flesh. Be clothed with Christ. Victory is for you.