Timothy Keller says, there are two great thieves of the Gospel truth:
He is building upon what C.S. Lewis once said, there are two ways we miss God. Either, (1) we feel really good about ourselves because we are “moral” and live a clean life. Or, (2) we live our lives however we see fit; for all the pleasure we can find.
Thief #1, moralism, says there is a standard, and we can meet it ourselves. In religious circles, some of us may recognize this as “legalism.” Legalism is religious moralism. It robs me from the joy of my salvation, because it leads me to feel superior or inferior based solely on my own works. Not, the work of Christ on my behalf.
Thief #2, relativism, says there is no standard! So, why bother trying to live life for anything, but personal pleasure and gain. If God does accept me, it’s because he is cool and loving; not, because He is forgiving my sin. I never fully understand “why” Jesus had to die, because I don’t take seriously the need for my sin’s atonement.
Keller argues, both thieves function the same; that is, both help us avoid Jesus, as our Savior and keep us in control.
The Gospel is this: through the person and work of Jesus Christ, God fully accomplishes salvation for us.
So, the moralist through the Gospel understands, God is more Holy than he can grasp. The relativist, through the Gospel sees God is more merciful and loving than he can understand.
Paul exhorts us in Colossians 1:23 to “remain steadfast in the hope of the gospel that you heard.”
The Gospel saves, sanctifies, and secures.
To go further with this teaching, listen to the message, “Religion Saves.” Also, pick up “The Prodigal God” by Timothy Keller.