Tractates on the Gospel of John

⁷ And since this is the case, do you, whoever you be, who are doubtless many of you still babes in Christ, be making advances towards the solid food of the mind, not of the belly. Grow in the ability to distinguish good from evil, and cleave more and more to the Mediator, who delivers you from evil; which does not admit of a local separation from you, but rather of being healed within you. But whoever shall say to you, Believe not Christ to be truly man, or that the body of any man or animal whatever was created by the true God, or that the Old Testament was given by the true God, and anything else of the same sort, for such things as these were not told you previously, when your nourishment was milk, because your heart was still unfit for the apprehension of the truth: such an one provides you not with meat, but with poison.

For therefore it was that the blessed apostle, in addressing those who appeared to him already perfect, even after calling himself imperfect, said, “Let us, therefore, as many as be perfect, be thus minded: and if in anything ye be otherwise minded, God shall reveal even this unto you.” And that they might not rush into the hands of seducers, whose desire would be to turn them away from the faith by promising them the knowledge of the truth, and suppose such to be the meaning of the apostle's words, “God shall reveal even this unto you,” he immediately added, “Nevertheless, whereto we have already attained, let us walk by the same rule.” If, then, you have come to some understanding of what is not at variance with the rule of the Catholic faith, whereto you have attained as the way that is guiding you to your fatherland; and hast so understood it as to feel it a duty to dismiss all doubts whatever on the subject: add to the building, but do not abandon the foundation.

And surely of such a character ought to be any teaching given by elders to those who are babes, as not to involve the assertion that Christ the Lord of all, and the prophets and apostles, who are much farther advanced in age than themselves, had in any respect spoken falsely. And not only ought you to avoid the babbling seducers of the mind, who prate away at their fables and falsehoods, and in such vanities make the promise, forsooth, of profound science contrary to the rule of faith, which we have accepted as Catholic; but avoid those also as a still more insidious pest than the others, who discuss truthfully enough the immutability of the divine nature, or the incorporeal creature, or the Creator, and fully prove what they affirm by the most conclusive documents and reasonings, and yet attempt to turn you away from the one Mediator between God and men.

For such are those of whom the apostle says, “Because that, when they knew God, they glorified Him not as God.” For what advantage is it to have a true understanding of the immutable Good to one who has no hold of Him by whom there is deliverance from evil? And let not the admonition of the most blessed apostle by any means lose its place in your hearts: “If any man preach any other gospel unto you than that you have received, let him be accursed.” He does not say, More than you have received; but, “Other than you have received.”

For had he said the former, he would be prejudging himself, inasmuch as he desired to come to the Thessalonians to supply what was lacking in their faith. But one who supplies, adds to what was deficient, without taking away what existed: while he that transgresses the rule of faith, is not progressing in the way, but turning aside from it.