Talk about pulling something completely out of context this is it. Augustine wrote this to confront the Mani heresy.
This is not the place to attempt any account or criticism of the strange eclecticism of Mani.[9] An adequate idea of the system may be gathered from the accompanying treatises. It may, however, be desirable to give some account of the original sources of information regarding it.
We study the systems of heresiarchs at a disadvantage when our only means of ascertaining their opinions is from the fragmentary quotations and hostile criticism which occur in the writings of their adversaries. Such, however, is our only source of information regarding the teaching of Mani. Originally, indeed, this heresy was specially active in a literary direction, assailing the Christian Scriptures with an ingenuity of unbelief worthy of a later age, and apparently ambitious of promulgating a rival canon. Certainly the writings of its early supporters were numerous;[10] and from the care and elegance with which they were transcribed, the sumptuous character of the manuscripts, and the mysterious emblems with which they were adorned, we should fancy it was intended to inspire the people with respect for an authoritative though as yet undefined code. It is, indeed, nowhere said or implied that the sacred books of the Manichæans were reserved for the eye only of the initiated or elect; and their reception of the New Testament Scriptures (subject to their own revision and emendation) would make it difficult for them to establish any secret code apart from these writings. They were certainly, however, doctrines of an esoteric kind, which were not divulged to the catechumens or hearers; and many of their books, being written in Persian, Syriac, or Greek, were practically unavailable for the instruction of the Latin speaking population. It was not always easy, therefore, to obtain an accurate knowledge of their opinions. Commentaries on the whole of the Old and New Testaments were written by Hierax;[11] a Theosophy by Aristocritus; a book of memoirs, or rather Memorabilia, of Mani, and other works, by Heraclides, Aphthonius, Adas, and Agapius. Unfortunately all of these books have perished, whether in the flames to which the Christian authorities commanded that all Manichæan books should be consigned, or by the slower if not more critical and impartial processes of time.
Mani himself was the author of several works: a Gospel, the Treasury of Life (and probably an abridgment of the same), the Mysteries, the Foundation Fpistle, a book of Articles or heads of doctrine, one or two works on astronomy or astrology, and a collection of letters so dangerous, that Manichæans who sought restoration to the Church were required to anathematize them. Mani Heresy