Guilty of Guilt - James Sire
James Sire, in a book called the Universe Next Door does and excellent job of explaining that people who hold to a naturalistic worldview can have no real foundation for ethics, but there still arises feelings of guilt. The problem is, in this type of world there is no solution to the guilt.
"In a universe where God is dead, people are not guilty of violating a moral law, they are only guilty of guilt, and that is a very serious, for nothing can be done about it. If one had sinned, there might be atonement. If one had broken a law, the lawmaker might forgive the criminal. But if one is only guilty of guilt, there is no way to solve the very personal problem. And that states the case of the nihilist, for no one can avoid acting as if moral values exist and as if there is some bar of justice that measures guilt by objective standards. But there is no bar of justice and we are left not in sin but in guilt. Very serious indeed."
-James Sire, The Universe Next Door-
Praise God for His moral law, and praise Him more for His atonement.