It is impossible for anyone in the Christian world to lack a concept of sin. Everyone in Christianity from early childhood on is taught what evil is, and from youth on is taught which evils are sinful… The evil that is simply evil against our neighbor, and evil against our neighbor is evil against God, which is what sin is.
Nevertheless, having a concept of sin does nothing for us unless examine the actions we have taken in our lives and see whether we have either openly or secretly done any such thing.
Before we take this action, everything about sin is just an idea to us; what the preacher says about it is only a sound that comes in our left ear, goes out our right ear, and is gone. Eventually it becomes a subject relegated to vague thoughts and mumbled words in worship, and for many it comes to seem like something imaginary and mythical.
Something completely different occurs, however, if we examine ourselves in the light of our concepts of what is sinful, discover some such thing in ourselves, say to ourselves, “This evil is sinful,” and then abstain from it out of fear of eternal punishment. Then for the first time we receive the instructive and eloquent preaching in church in both of our ears, take it to heart, and turn from a non-Christian into a Christian.
from Regeneration, Pages 28, 29