Paul loved to liken the Christian life to a race in the arena. Notice that to 'run well' in the Christian race is not just to believe the truth (as if Christianity were nothing but orthodoxy), nor just to behave well (as if it were just moral uprightness), but to 'obey the truth', applying belief to behaviour. Only he who obeys the truth is an integrated Christian. What he believes and how he behaves are all of a piece. His creed is expressed in his conduct; his conduct is derived from his creed.
--Excerpted from "Authentic Christianity", p. 216, by permission of InterVarsity Press.