A sundial only works when there is light. It does not work at midnight in a fog. Moreover it requires light from the proper source. The moon makes it point to the wrong time. Take a flashlight with you and walk around a sundial at 3 a.m. It will tell you whatever time you want. Conscience, likewise, functions only when it has the light of God's Word illuminated by God's Spirit shining on it.
The Fight: A Practical Handbook for Christian Living