Concerning the Nature of Good, Against the Manichaeans

But for the sake of those who, not being able to understand that all nature, that is, every spirit and every body, is naturally good, are moved by the iniquity of spirit and the mortality of body, and on this account endeavor to bring in another nature of wicked spirit and mortal body, which God did not make, we determine thus to bring to their understanding what we say can be brought. For they acknowledge that no good thing can exist save from the highest and true God, which also is true and suffices for correcting them, if they are willing to give heed.