5 Augustine replied: O hateful mixture of ignorance and cunning! Why do you put arguments in the mouth of your opponent, which no one that knows you would use? We do not call you Pagans, or a schism of Pagans; but we say that you resemble them in worshipping many gods. But you are far worse than Pagans, for they worship things which exist, though they should not be worshipped: for idols have an existence, though for salvation they are nought. So, to worship a tree with prayers, instead of improving it by cultivation, is not to worship nothing, but to worship in a wrong way.
When the apostle says that "the things which the Gentiles sacrifice, they sacrifice to demons, and not to God," he means that these demons exist to whom the sacrifices are made, and with whom he wishes us not to be partakers. So, too, heaven and earth, the sea and air, the sun and moon, and the other heavenly bodies, are all objects which have a sensible existence. When the Pagans worship these as gods, or as parts of one great God (for some of them identify the universe with the Supreme Deity), they worship things which have an existence.
In arguing with Pagans, we do not deny the existence of these things, but we say that they should not be worshipped; and we recommend the worship of the invisible Creator of all these things, in whom alone man can find the happiness which all allow that he desires. To those, again, who worship what is invisible and immaterial, but still is created, as the soul or mind of man, we say that happiness is not to be found in the creature even under this form, and that we must worship the true God, who is not only invisible, but unchangeable; for He alone is to be worshipped, in the enjoyment of whom the worshipper finds happiness, and without whom the soul must be wretched, whatever else it possesses.
You, on the other hand, who worship things which have no existence at all except in your fictitious legends, would be nearer true piety and religion if you were Pagans, or if you were worshippers of what has an existence, though not a proper object of worship. In fact, you do not properly worship the sun, though he carries your prayers with him in his course round the heavens.
Source: Reply to Faustus the Manichaean (New Advent)