# Nicene and Post-Nicene Fathers: Series I/Volume II/On Christian Doctrine/Book III/Chapter 30

Chapter 30.—The Rules of Tichonius the Donatist Examined.
42. One Tichonius, who, although a Donatist himself, has written most triumphantly against the Donatists (and herein showed himself of a most inconsistent disposition, that he was unwilling to give them up altogether), wrote a book which he called the Book of Rules, because in it he laid down seven rules, which are, as it were, keys to open the secrets of Scripture. And of these rules, the first relates to the Lord and His body, the second to the twofold division of the Lord’s body, the third to the promises and the law, the fourth to species and genus, the fifth to times, the sixth to recapitulation, the seventh to the devil and his body. Now these rules, as expounded by their author, do indeed, when carefully considered, afford considerable assistance in penetrating the secrets of the sacred writings; but still they do not explain all the difficult passages, for there are several other methods required, which are so far from being embraced in this number of seven, that the author himself explains many obscure passages without using any of his rules; finding, indeed, that there was no need for them, as there was no difficulty in the passage of the kind to which his rules apply. As, for example, he inquires what we are to understand in the Apocalypse by the seven angels of the churches to whom John is commanded to write; and after much and various reasoning, arrives at the conclusion that the angels are the churches themselves. And throughout this long and full discussion, although the matter inquired into is certainly very obscure, no use whatever is made of the rules. This is enough for an example, for it would be too tedious and troublesome to collect all the passages in the canonical Scriptures which present obscurities of such a kind as require none of these seven rules for their elucidation.
43. The author himself, however, when commending these rules, attributes so much value to them that it would appear as if, when they were thoroughly known and duly applied, we should be able to interpret all the obscure passages in the law—that is, in the sacred books. For he thus commences this very book: “Of all the things that occur to me, I consider none so necessary as to write a little book of rules, and, as it were, to make keys for, and put windows in, the secret places of the law. For there are certain mystical rules which hold the key to the secret recesses of the whole law, and render visible the treasures of truth that are to many invisible. And if this system of rules be received as I communicate it, without jealousy, what is shut shall be laid open, and what is obscure shall be elucidated, so that a man travelling through the vast forest of prophecy shall, if he follow these rules as pathways of light, be preserved from going astray.” Now, if he had said, “There are certain mystical rules which hold the key to some of the secrets of the law,” or even “which hold the key to the great secrets of the law,” and not what he does say, “the secret recesses of the whole law;” and if he had not said “What is shut shall be laid open,” but, “Many things that are shut shall be laid open,” he would have said what was true, and he would not, by attributing more than is warranted by the facts to his very elaborate and useful work, have led the reader into false expectations. And I have thought it right to say thus much, in order both that the book may be read by the studious (for it is of very great assistance in understanding Scripture), and that no more may be expected from it than it really contains. Certainly it must be read with caution, not only on account of the errors into which the author falls as a man, but chiefly on account of the heresies which he advances as a Donatist. And now I shall briefly indicate what these seven rules teach or advise.