Why the somber face?

Our hope for this world and for the world to come is a High Priest, an altar, a temple, a tabernacle, a shrine and a Savior by the throne above. This we Christians have. What bothers me is how we can keep so quiet about it and why it is that we can take it so soberly, almost sadly. It would seem to me that we Christians ought to be the happiest people in the whole wide world.—A.W. Tozer, Experiencing the Presence of God, 92