Religious symbols point symbolically to that which transcends all of them. But since, as symbols, they participate in that to which they point, they always have the tendency (in the human mind, of course) to replace that to which they are supposed to point, and to become ultimate in themselves. And in the moment in which they do this, they become idols. All idolatry is nothing else than the absolutizing of symbols of the Holy, and making them identical with the Holy itself. In this way, for instance, holy persons can become god. Ritual acts can take on unconditional validity, although they are only expressions of a special situation. In all sacramental activities of religion, in all holy objects, holy books, holy doctrines, holy rites, you find this danger which I like to call demonization. They become demonic in the moment in which they become elevated to the unconditional and ultimate character of the Holy itself.
from The Christian Scholar
(transcribed from a speech given at Shimer College, Mt Carmel, Illinois)