4 Faustus glibly defends himself by saying, "We speak not of two gods, but of God and Hyle." But when you ask for the meaning of Hyle, you find that it is in fact another god. If the Manichæans gave the name of Hyle, as the ancients did, to the unformed matter which is susceptible of bodily forms, we should not accuse them of making two gods. But it is pure folly and madness to give to matter the power of forming bodies, or to deny that what has this power is God.
When you give to some other being the power which belongs to the true God of making the qualities and forms, by which bodies, elements, and animals exist, according to their respective modes, whatever name you choose to give to this being, you are chargeable with making another god. There are indeed two errors in this blasphemous doctrine. In the first place, you ascribe the act of God to a being whom you are ashamed to call god; though you must call him god as long as you make him do things which only God can do.
In the second place, the good things done by a good God you call bad, and ascribe to an evil god, because you feel a childish horror of whatever shocks the frailty of fallen humanity, and a childish pleasure in the opposite. So you think snakes are made by an evil being; while you consider the sun so great a good, that you believe it to be not the creature of God, but an emission from His substance. You must know that the true God, in whom, alas, you have not yet come to believe, made both the snake along with the lower creatures, and the sun along with other exalted creatures.
Moreover, among still more exalted creatures, not heavenly bodies, but spiritual beings, He has made what far surpasses the light of the sun, and what no carnal man can perceive, much less you, who, in your condemnation of flesh, condemn the very principle by which you determine good and evil. For your only idea of evil is from the disagreeableness of some things to the fleshly sense; and your only idea of good is from sensual gratification.
Source: Reply to Faustus the Manichaean (New Advent)