I confess I would almost rather be charged with a religion that extenuated murder, than with one that justified idolatry. Murder, great as the offense is, is but the slaying of man; but idolatry is, in its essence, the killing of God.
Charles Spurgeon
Man’s mind is like a store of idolatry and superstition; so much so that if a man believes his own mind it is certain that he will forsake God and forge some idol in his own brain.
John Calvin (French Reformer)
Idolatry is not only the adoration of images … but also trust in one’s own righteousness, works, and merits, and putting confidence in riches and power.