Several forms of idolatry have been distinguished. Gross, or overt, idolatry consists of explicit acts of reverence addressed to a person or an object—the sun, the king, an animal, a statue. This may exist alongside the acknowledgment of a supreme being; e.g., Israel worshiped the golden calf at the foot of Mount Sinai, where it had encamped to receive the Law and the covenant of the one true God.

A person becomes guilty of a more subtle idolatry, however, when, although overt acts of adoration are avoided, he attaches to a creature the confidence, loyalty, and devotion that properly belong only to the Creator. Thus, the nation is a good creature of God, but it is to be loved and served with an affection appropriate to it, not with the ultimate devotion that must be reserved for the Lord of all nations. Even true doctrine (e.g., true doctrine about idolatry) may become an idol if it fails to point beyond itself to God alone.

At the same time, Christian (Christianity) thought has insisted upon the principle of mediation and has rejected the charge that attachment to a mediating agency is automatically idolatrous. The Christian scriptures are called “the Holy Bible” not because they have an intrinsic holiness or are themselves the source of such holiness but because the God who alone is holy is mediated and disclosed to humans through the words of the Bible. Christians are not in agreement about the agents of mediation—e.g., about the role of the Virgin Mary and of the other saints. But where such mediation is acknowledged to be present, it is also acknowledged that reverence shown toward it applies not to the agent of mediation in and of himself but to the one for whom the agent stands. A special instance is the human nature of Jesus Christ (which is worthy of divine worship because of its inseparable union with the Second Person of the Holy Trinity) and the consecrated Host in the Eucharist (which may properly be adored because it has been changed into the very body of Christ). Although the accusation of idolatry is thus a part of the polemic of Christian against Christian, so that Protestants are accused of bibliolatry and Roman Catholics of Mariolatry, the fundamental meaning of the term is the direct moral corollary of the Jewish-Christian avowal of the oneness of God: “Hear, O Israel: The Lord our God is one Lord.”

see also aniconism.