Let us beware lest we in our pride accept the erroneous notion that idolatry consists only in kneeling before visible objects of adoration, and that civilized peoples are therefore free from it. The essence of idolatry is the entertainment of thoughts about God that are unworthy of Him. It begins in the mind and may be present where no overt act of worship has taken place. “When they knew God,” wrote Paul, “they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened.”
Then followed the worship of idols fashioned after the likeness of men and birds and beasts and creeping things. But this series of degrading acts began in the mind. Wrong ideas about God are not only the fountain from which the polluted waters of idolatry flow; they are themselves idolatrous. The idolater simply imagines things about God and acts as if they were true.
Perverted notions about God soon rot the religion in which they appear. The long career of Israel demonstrates this clearly enough, and the history of the Church confirms it. So necessary to the Church is a lofty concept of God that when that concept in any measure declines, the Church with her worship and her moral standards declines along with it. The first step down for any church is taken when it surrenders its high opinion of God. - A. W. Tozer, The Knowledge of the Holy (San Francisco: HaperCollins, 1961), 3-4.