For I know that in me (that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not.
There can be no progress in holiness until we learn what Paul learned here – “that in me, (that is, in my flesh) dwelleth no good thing”. The flesh here means the evil, corrupt nature which we inherited from Adam and which is still in every believer. It is the source of every evil action which a person performs and there is nothing good in it. When we learn this – 1) it delivers us from ever looking for any good in the old nature, 2) it delivers us from being disappointed when we don’t find any good there, 3) it delivers us from occupation with ourselves. To confirm the hopelessness of the flesh, Paul mourned that although he had the desire to do what is right, he doesn’t have the resources in himself to translate his desire into action.