Sin is the despairing refusal to find your deepest identity in your relationship and service to God. Sin is seeking to become oneself, to get an identity apart from him.....
Most people think of sin primarily as “breaking divine rules,” but Kierkegaard knows that the very first of the Ten Commandments is to “have no other gods before me.”
So, according to the Bible, the primary way to define sin is not just the doing of bad things, but the making of good things into ultimate things. It is seeking to establish a sense of self by making something else more central to your significance, purpose, and happiness than your relationship to God.
-Tim Keller, The Reason For God