Paul, early and often, contrasts empty thinking and lawless behavior with genuine Christian concern. The goal of the command is a clear conscience, an unhypocritical faith, and a sincere love. Anything less and you are sidetracked. The vices listed in this chapter are the polar opposites of the goal of God's commands. The law of God was being misused and as a result it had no power to control all kinds of bad behavior.
It is a faithful saying that Jesus Christ came into the world to save sinners -- of whom I am first. As he contemplates the mercy and patience of God, he breaks into praise! If we realize we are sinners in desperate need of saving, and understand God has sent Jesus to be that savior, and that He'd do it for me. . . I can't help but breakout in thanksgiving!
He talks about fighting the good fight. How are we supposed to do that? By having faith and a good conscience in the commands. In other words, we fight the good fight with God's word.