On the contrary, It is written ( Ex. 20:5 ): "Thou shalt not adore them," i.e. outwardly, "nor serve them," i.e. inwardly, as a gloss explains it: and it is a question of graven things and images. Therefore it is a sin to worship idols whether outwardly or inwardly.
I answer that, There has been a twofold error in this matter. For some [*The School of Plato] have thought that to offer sacrifices and other things pertaining to latria, not only to God but also to the others aforesaid, is due and good in itself, since they held that divine honor should be paid to every superior nature, as being nearer to God. But this is unreasonable. For though we ought to revere all superiors, yet the same reverence is not due to them all: and something special is due to the most high God Who excels all in a singular manner: and this is the worship of latria.
Nor can it be said, as some have maintained, that "these visible sacrifices are fitting with regard to other gods, and that to the most high God, as being better than those others, better sacrifices, namely, the service of a pure mind, should be offered" [*Augustine, as quoted below]. The reason is that, as Augustine says (De Civ. Dei x, 19), "external sacrifices are signs of internal, just as audible words are signs of things. Wherefore, just as by prayer and praise we utter significant words to Him, and offer to Him in our hearts the things they signify, so too in our sacrifices we ought to realize that we should offer a visible sacrifice to no other than to Him Whose invisible sacrifice we ourselves should be in our hearts."
Others held that the outward worship of latria should be given to idols, not as though it were something good or fitting in itself, but as being in harmony with the general custom. Thus Augustine (De Civ. Dei vi, 10) quotes Seneca as saying: "We shall adore," says he, "in such a way as to remember that our worship ss in accordance with custom rather than with the reality": and (De Vera Relig. v) Augustine says that "we must not seek religion from the philosophers, who accepted the same things for sacred, as did the people; and gave utterance in the schools to various and contrary opinions about the nature of their gods, and the sovereign good." This error was embraced also by certain heretics [*The Helcesaitae], who affirmed that it is not wrong for one who is seized in time of persecution to worship idols outwardly so long as he keeps the faith in his heart.
But this is evidently false. For since outward worship is a sign of the inward worship, just as it is a wicked lie to affirm the contrary of what one holds inwardly of the true faith so too is it a wicked falsehood to pay outward worship to anything counter to the sentiments of one's heart. Wherefore Augustine condemns Seneca (De Civ. Dei vi, 10) in that "his worship of idols was so much the more infamous forasmuch as the things he did dishonestly were so done by him that the people believed him to act honestly."
Reply to Objection 1: Neither in the Tabernacle or Temple of the Old Law, nor again now in the Church are images set up that the worship of latria may be paid to them, but for the purpose of signification, in order that belief in the excellence of angels and saints may be impressed and confirmed in the mind of man. It is different with the image of Christ, to which latria is due on account of His Divinity, as we shall state in the TP, Q[25], A[3].
The Replies to the Second and Third Objections are evident from what has been said above.
Whether idolatry is the gravest of sins?
Objection 1: It would seem that idolatry is not the gravest of sins. The worst is opposed to the best (Ethic. viii, 10). But interior worship, which consists of faith, hope and charity, is better than external worship. Therefore unbelief, despair and hatred of God, which are opposed to internal worship, are graver sins than idolatry, which is opposed to external worship.
Objection 2: Further, the more a sin is against God the more grievous it is. Now, seemingly, a man acts more directly against God by blaspheming, or denying the faith, than by giving God's worship to another, which pertains to idolatry. Therefore blasphemy and denial of the faith are more grievous sins than idolatry.
Objection 3: Further, it seems that lesser evils are punished with greater evils. But the sin of idolatry was punished with the sin against nature, as stated in Rom. 1:26. Therefore the sin against nature is a graver sin than idolatry.
Objection 4: Further, Augustine says (Contra Faust. xx, 5): "Neither do we say that you," viz. the Manichees, "are pagans, or a sect of pagans, but that you bear a certain likeness to them since you worship many gods: and yet you are much worse than they are, for they worship things that exist, but should not be worshiped as gods, whereas you worship things that exist not at all." Therefore the vice of heretical depravity is more grievous than idolatry.
Objection 5: Further, a gloss of Jerome on Gal. 4:9, "How turn you again to the weak and needy elements?" says: "The observance of the Law, to which they were then addicted, was a sin almost equal to the worship of idols, to which they had been given before their conversion." Therefore idolatry is not the most grievous sin.
On the contrary, A gloss on the saying of Lev. 15:25, about the uncleanness of a woman suffering from an issue of blood, says: "Every sin is an uncleanness of the soul, but especially idolatry."
I answer that, The gravity of a sin may be considered in two ways. First, on the part of the sin itself, and thus idolatry is the most grievous sin. For just as the most heinous crime in an earthly commonwealth would seem to be for a man to give royal honor to another than the true king, since, so far as he is concerned, he disturbs the whole order of the commonwealth, so, in sins that are committed against God, which indeed are the greater sins, the greatest of all seems to be for a man to give God's honor to a creature, since, so far as he is concerned, he sets up another God in the world, and lessens the divine sovereignty. Secondly, the gravity of a sin may be considered on the part of the sinner. Thus the sin of one that sins knowingly is said to be graver than the sin of one that sins through ignorance: and in this way nothing hinders heretics, if they knowingly corrupt the faith which they have received, from sinning more grievously than idolaters who sin through ignorance. Furthermore other sins may be more grievous on account of greater contempt on the part of the sinner.
Reply to Objection 1: Idolatry presupposes internal unbelief, and to this it adds undue worship. But in a case of external idolatry without internal unbelief, there is an additional sin of falsehood, as stated above (A[2]).
Reply to Objection 2: Idolatry includes a grievous blasphemy, inasmuch as it deprives God of the singleness of His dominion and denies the faith by deeds.
Reply to Objection 3: Since it is essential to punishment that it be against the will, a sin whereby another sin is punished needs to be more manifest, in order that it may make the man more hateful to himself and to others; but it need not be a more grievous sin: and in this way the sin against nature is less grievous than the sin of idolatry. But since it is more manifest, it is assigned as a fitting punishment of the sin of idolatry, in order that, as by idolatry man abuses the order of the divine honor, so by the sin against nature he may suffer confusion from the abuse of his own nature.
Reply to Objection 4: Even as to the genus of the sin, the Manichean heresy is more grievous than the sin of other idolaters, because it is more derogatory to the divine honor, since they set up two gods in opposition to one another, and hold many vain and fabulous fancies about God. It is different with other heretics, who confess their belief in one God and worship Him alone.
Reply to Objection 5: The observance of the Law during the time of grace is not quite equal to idolatry as to the genus of the sin, but almost equal, because both are species of pestiferous superstition.
Whether the cause of idolatry was on the part of man?
Objection 1: It would seem that the cause of idolatry was not on the part of man. In man there is nothing but either nature, virtue, or guilt. But the cause of idolatry could not be on the part of man's nature, since rather does man's natural reason dictate that there is one God, and that divine worship should not be paid to the dead or to inanimate beings. Likewise, neither could idolatry have its cause in man on the part of virtue, since "a good tree cannot bring forth evil fruit," according to Mat. 7:18 : nor again could it be on the part of guilt, because, according to Wis. 14:27, "the worship of abominable idols is the cause and the beginning and end of all evil." Therefore idolatry has no cause on the part of man.
Objection 2: Further, those things which have a cause in man are found among men at all times. Now idolatry was not always, but is stated [*Peter Comestor, Hist. Genes. xxxvii, xl] to have been originated either by Nimrod, who is related to have forced men to worship fire, or by Ninus, who caused the statue of his father Bel to be worshiped. Among the Greeks, as related by Isidore (Etym. viii, 11), Prometheus was the first to set up statues of men: and the Jews say that Ismael was the first to make idols of clay. Moreover, idolatry ceased to a great extent in the sixth age. Therefore idolatry had no cause on the part of man.
Objection 3: Further, Augustine says (De Civ. Dei xxi, 6): "It was not possible to learn, for the first time, except from their" (i.e. the demons') "teaching, what each of them desired or disliked, and by what name to invite or compel him: so as to give birth to the magic arts and their professors": and the same observation seems to apply to idolatry. Therefore idolatry had no cause on the part of man.
On the contrary, It is written ( Wis. 14:14 ): "By the vanity of men they," i.e. idols, "came into the world."