The Divine Institutes

Now let us instruct those who are ignorant of the truth. It has been so determined by the arrangement of the Most High God, that this unrighteous age, having run the course of its appointed times, should come to an end; and all wickedness being immediately extinguished, and the souls of the righteous being recalled to a happy life, a quiet, tranquil, peaceful, in short, golden age, as the poets call it, should flourish, under the rule of God Himself. This was especially the cause of all the errors of the philosophers, that they did not comprehend the system of the world, which comprises the whole of wisdom. But it cannot be comprehended by our own perception and innate intelligence, which they wished to do by themselves without a teacher. Therefore they fell into various and ofttimes contradictory opinions, out of which they had no way of escape,

…as the comic writer says, since their conclusion does not correspond with their assumptions; inasmuch as they had assumed things to be true which could not be affirmed, and proved without the knowledge of the truth and of heavenly things. And this knowledge, as I have often said already, cannot exist in a man unless it is derived from the teaching of God. For if a man is able to understand divine things, he will be able also to perform them; for to understand is, as it were, to follow in their track. But he is not able to do the things which God does, because he is clothed with a mortal body; therefore he cannot even understand those things which God does. And whether this is possible is easy for every one to measure, from the immensity of the divine actions and works. For if you will contemplate the world, with all the things which it contains, you will assuredly understand how much the work of God surpasses the works of men. Thus, as great as is the difference between divine and human works, so great must be the distance between the wisdom of God and man. For because God is incorruptible and immortal, and therefore perfect because He is everlasting, His wisdom also is perfect, as He Himself is; nor can anything oppose it, because God Himself is subject to nothing.

But because man is subject to passion, his wisdom also is subject to error; and as many things hinder the life of man, so that it cannot be perpetual, so also his wisdom must be hindered by many things: so that it is not perfect in entirely perceiving the truth. Therefore there is no human wisdom, if it strives by itself to attain to the conception and knowledge of the truth; inasmuch as the mind of man, being bound up with a frail body, and enclosed in a dark abode, is neither able to wander at large, nor clearly to perceive the truth, the knowledge of which belongs to the divine nature. For His works are known to God alone. But man cannot attain this knowledge by reflection or disputation, but by learning and hearing from Him who alone is able to know and to teach. Therefore Marcus Tullius, borrowing from Plato the sentiment of Socrates, who said that the time had come for himself to depart from life, but that they before whom he was pleading his cause were still alive, says: Which is better is known to the immortal gods; but I think that no man knows. Wherefore all the sects of philosophers must be far removed from the truth, because they who established them were men; nor can those things have any foundation or firmness which are unsupported by any utterances of divine voices.