For where the Church is, there is the Spirit of God; and where the Spirit of God is, there is the Church, and every kind of grace; but the Spirit is truth. Those, therefore, who do not partake of Him, are neither nourished into life from the mother’s breasts, nor do they enjoy that most limpid fountain which issues from the body of Christ; but they dig for themselves broken cisterns Jeremiah 2:13 out of earthly trenches, and drink putrid water out of the mire, fleeing from the faith of the Church lest they be convicted; and rejecting the Spirit, that they may not be instructed.

Alienated thus from the truth, they do deservedly wallow in all error, tossed to and fro by it, thinking differently in regard to the same things at different times, and never attaining to a well-grounded knowledge, being more anxious to be sophists of words than disciples of the truth. For they have not been founded upon the one rock, but upon the sand, which has in itself a multitude of stones. Wherefore they also imagine many gods, and they always have the excuse of searching [after truth] (for they are blind), but never succeed in finding it. For they blaspheme the Creator, Him who is truly God, who also furnishes power to find [the truth]; imagining that they have discovered another god beyond God, or another Pleroma, or another dispensation. Wherefore also the light which is from God does not illumine them, because they have dishonored and despised God, holding Him of small account, because, through His love and infinite benignity, He has come within reach of human knowledge (knowledge, however, not with regard to His greatness, or with regard to His essence— for that has no man measured or handled — but after this sort: that we should know that He who made, and formed, and breathed in them the breath of life, and nourishes us by means of the creation, establishing all things by His Word, and binding them together by His Wisdom — this is He who is the only true God); but they dream of a non-existent being above Him, that they may be regarded as having found out the great God, whom nobody, [they hold,] can recognise holding communication with the human race, or as directing mundane matters: that is to say, they find out the god of Epicurus, who does nothing either for himself or others; that is, he exercises no providence at all. —from Against Heresies (Book III, Chapter 24)