I take a page from Kierkegaard’s The Sickness Unto Death and define sin as building your identity "your self-worth and happiness" on anything other than God. That is, I use the biblical definition of sin as idolatry. That puts the emphasis not as much on "doing bad things" but on "making good things into ultimate things.
Tim Keller – American Pastor
Website: http://www.christianitytoday.com/le/2008/002/9.74.html