An idol is something that we look to for things that only God can give. Idolatry functions widely inside religious communities when doctrinal truth is elevated to the position of a false god. This occurs when people rely on the rightness of their doctrine for their standing with God rather than on God himself and his grace. It is a subtly but deadly mistake. The sign that you have slipped into this form of self-justification is that you become what the book of Proverbs calls a 'scoffer'.