But the knowledge of those who think themselves wise, whether the barbarian sects or the philosophers among the Greeks, according to the apostle, “puffeth up.”[102] But that knowledge, which is the scientific demonstration of what is delivered according to the true philosophy, is founded on faith. Now, we may say that it is that process of reason which, from what is admitted, procures faith in what is disputed. Now, faith being twofold--the faith of knowledge and that of opinion--nothing prevents us from calling demonstration twofold, the one resting on knowledge, the other on opinion; since also knowledge and foreknowledge are designated as twofold, that which is essentially accurate, that which is defective. And is not the demonstration, which we possess, that alone which is true, as being supplied out of the divine Scriptures, the sacred writings, and out of the “God-taught wisdom,” according to the apostle? Learning, then, is also obedience to the commandments, which is faith in God. And faith is a power of God, being the strength of the truth. For example, it is said, “If ye have faith as a grain of mustard, ye shall remove the mountain.”[103] And again, “According to thy faith let it be to thee.”[104] And one is cured, receiving healing by faith; and the dead is raised up in consequence of the power of one believing that he would be raised. The demonstration, however, which rests on opinion is human, and is the result of rhetorical arguments or dialectic syllogisms. For the highest demonstration, to which we have alluded, produces intelligent faith by the adducing and opening up of the Scriptures to the souls of those who desire to learn; the result of which is knowledge (_gnosis_). For if what is adduced in order to prove the point at issue is assumed to be true, as being divine and prophetic, manifestly the conclusion arrived at by inference from it will consequently be inferred truly; and the legitimate result of the demonstration will be knowledge. When, then, the memorial of the celestial and divine food was commanded to be consecrated in the golden pot, it was said, “The omer was the tenth of the three measures.”[105] For in ourselves, by the three measures are indicated three criteria; sensation of objects of sense, speech,--of spoken names and words, and the mind,--of intellectual objects. The Gnostic, therefore, will abstain from errors in speech, and thought, and sensation, and action, having heard “that he that looks so as to lust hath committed adultery;”[106] and reflecting that “blessed are the pure in heart, for they shall see God;”[107] and knowing this, “that not what enters into the mouth defileth, but that it is what cometh forth by the mouth that defileth the man. For out of the heart proceed thoughts.”[108] This, as I think, is the true and just measure according to God, by which things capable of measurement are measured, the decad which is comprehensive of man; which summarily the three