Notwithstanding, those who have written in this manner regarding the “chief good” will go down to the Piræus and offer prayer to Artemis, as if she were God, and will look (with approval) upon the solemn assembly held by ignorant men; and after giving utterance to philosophical remarks of such profundity regarding the soul, and describing its passage (to a happier world) after a virtuous life, they pass from those great topics which God has revealed to them, and adopt mean and trifling thoughts, and offer a cock to Æsculapius! And although they had been enabled to form representations both of the “invisible things” of God and of the “archetypal forms” of things from the creation of the world, and from (the contemplation of) sensible things, from which they ascend to those objects which are comprehended by the understanding alone—and although they had no mean glimpses of His “eternal power and Godhead,” they nevertheless became “foolish in their imaginations,” and their “foolish heart” was involved in darkness and ignorance as to the (true) worship of God.
Moreover, we may see those who greatly pride themselves upon their wisdom and theology worshipping the image of a corruptible man, in honour, they say, of Him, and sometimes even descending, with the Egyptians, to the worship of birds, and four-footed beasts, and creeping things! And although some may appear to have risen above such practices, nevertheless they will be found to have changed the truth of God into a lie, and to worship and serve the “creature more than the Creator.” As the wise and learned among the Greeks, then, commit errors in the service which they render to God, God “chose the foolish things of the world to confound the wise; and base things of the world, and things that are weak, and things which are despised, and things which are nought, to bring to nought things that are;” and this, truly, “that no flesh should glory in the presence of God.” Our wise men, however—Moses, the most ancient of them all, and the prophets who followed him—knowing that the chief good could by no means be described in words, were the first who wrote that, as God manifests Himself to the deserving, and to those who are qualified to behold Him, He appeared to Abraham, or to Isaac, or to Jacob. But who He was that appeared, and of what form, and in what manner, and like to which of mortal beings, they have left to be investigated by those who are able to show that they resemble those persons to whom God showed Himself: for He was seen not by their bodily eyes, but by the pure heart. For, according to the declaration of our Jesus, “Blessed are the pure in heart, for they shall see God.”
Source: Against Celsus (New Advent)