Being Displeased with Some Part Of God's Creation, He Conceives of Two Original Substances
20 There is no wholeness in them whom anything of Your creation displeased no more than there was in me, when many things which You made displeased me. And, because my soul dared not be displeased at my God, it would not allow anything to be Yours which displeased it. Hence it had gone into the opinion of two substances, and resisted not, but talked foolishly. And, returning thence, it had made to itself a god, through infinite measures of all space; and imagined it to be You, and placed it in its heart, and again had become the temple of its own idol, which was to You an abomination. But after You had fomented the head of me unconscious of it, and closed my eyes lest they should “behold vanity,” I ceased from myself a little, and my madness was lulled to sleep; and I awoke in You, and saw You to be infinite, though in another way; and this sight was not derived from the flesh.
Source: Confessions (New Advent)