Believing that “it is finished”, that everything we need in Christ is already ours and therefore we need nothing more, is the hardest thing (so much harder than modifying our behavior) because we are all seasoned “do-it-yourselfers.” Self-salvation engineers (that’s all of us) find it much easier to make a moral “to-do” and “not-to-do” list and try to live by it, then they do trusting, believing, and resting wholly in the work and provision of Another. “To be convinced in our hearts”, said Luther, “that we have forgiveness of sins and peace with God by grace alone is the hardest thing” because “the sin underneath all sins is the lie that we cannot trust the love and grace of Jesus and that we must take matters into our own hands.”
Failing to believe the gospel leads to slavery because now finding peace, joy, meaning, and satisfaction is up to me.
I’m on my own. This is why we give into temptation–we’re desperately
looking under every rock and behind every tree searching for something
to make ourselves happy, something to save us, something to set us free.
The gospel declares that I don’t need to save myself, defend myself,
legitimize myself, justify myself, free myself, or in any other way,
ensure that the ultimate verdict on my life is pass and not fail. The
gospel frees me from the obsessive pressure to avoid the judgement of
joylessness, the enslaving demand to find happiness. Walker Percy has
described humanity as waiting for news. Christianity announces that the
news has come: I’m not on my own. It’s not on me. We all know that
“further, better, and more aggressive living” on our part isn’t
producing life for us, and so the gospel comes as good news to those who
have crashed and burned. What I need and long for most has come from
outside of me–from “above the sun”–in the person of Jesus.
Real freedom in “the hour of temptation” happens only when the
resources of the gospel smash any sense of need to secure for myself
anything beyond what Christ has already secured for me.