When Paul realized that Jesus Christ loved him so much He was willing to give Himself to be crucified for him, he put his faith in Jesus Christ, the Son of God.  That step of faith so identified him with Jesus Christ that he saw himself as “crucified with Christ.”  This death to self, freed him to experience Christ living in him. 

It also freed him from the obligation to do his best to fulfill the law.  That only leads to self-righteousness.  He was dead to living that way, but very much alive in the body.  Rather than trying, he determined to trust in the indwelling Christ to live out His life in and through him.  He put it this way: “The life I live in the body, I live by faith in the Son of God” (who lives in me).  He’s the one “who loved me and gave himself for me.”

Later in the book he explains, as we receive Jesus Christ by faith we also receive the Spirit by faith.  This all happens when we are saved.  Since we receive the Spirit by faith we need to recognize that we are to rely on the Spirit as we continue our walk with Christ.  Too often we trust Christ for salvation and then try to live the Christian life by attempting to measure up to a standard by shear discipline.  Paul asks: “Are you so foolish?  After beginning with the Spirit, are you now trying to attain your goal by human effort?”

That’s a rhetorical question. Think about it.