Romans 7:15-17 ... The Living Bible  

I don't understand myself at all., for I really want to do what is right, but I can't.  I do what I don't want to ... what I hate.  I know perfectly well what I'm doing is wrong, and my bad conscience proves that I agree with these laws I am breaking.  But I can't help myself, because I'm no longer doing it.  It is sin inside me that is stronger than I am that makes me do these evil things.

Paul sounds like he's talking in riddles.  But he's correlating the difference between what he was and what he is now ... bringing in the spiritual side along with the soulish side.  He says, "In the spiritual side, I know that I shouldn't be doing this."  

Sometimes after we come to the Lord, are born again, we still do the "old desires", knowing that we shouldn't be doing these things but doing them anyway also.    

Reverend Robert W. & Mary C. Butler