Clement of Alexandria, Miscellanies 16

Those who are prepared to labor for the highest goods will not cease seeking the truth until they receive proof of it from the Scriptures. There are indeed certain criteria common to all people, such as the senses. But for those who have willed the truth and disciplined themselves in it, there are technical terms for truth and falsehood that operate through the mind and reasoning. The greatest step is to lay aside mere opinion. Taking a stand between precise knowledge and reckless pseudo-wisdom, one must recognize that the person who hopes for eternal rest also knows that the entrance to it is laborious and "narrow." The one who has once been evangelized and declares, "I have seen the salvation" (Luke 2:30), must not turn back to the things behind, like Lot's wife, at whatever hour he comes to recognize it; nor must he return to the former life that yields to the senses, nor waver back into heresies. For the heresies contend in some fashion, not knowing the God who truly exists. "Whoever loves father or mother more than me" (Matthew 10:37) — meaning the true Father and Teacher of truth, the one who regenerates, rebuilds, and nurtures the chosen soul — "is not worthy of me." Jesus says such a person is not worthy of being a son of God and a disciple of God, both friend and kinsman. "No one who puts a hand to the plow and looks back is fit for the kingdom of God" (Luke 9:62).

Yet, as it appears, to many even now Mary seems to be a woman who has given birth because of the child's birth, though she is not a woman who has given birth in the ordinary sense (for some say that after she bore him she was found to be a virgin still). Such are the Lord's Scriptures to us: they give birth to the truth yet remain virgins after the veiling of the mysteries of truth. "She has given birth and has not given birth," the Scripture says, as if from itself — not having conceived through sexual union. Therefore the Scriptures have been impregnated with truth for the Gnostics (the knowing ones), but the heresies, having not learned as if not having been impregnated, are sent away. All people possess the same faculty of judgment; some follow the choosing Word and form their convictions accordingly, while others, having surrendered themselves to pleasures, force Scripture to conform to their desires. But, I think, the lover of truth requires psychic strength; for those who attempt the greatest matters are bound to fail greatly unless they possess the standard of truth, having received it from truth itself. Such people, having fallen from the right path, rightly fail in most particulars, because they lack a criterion of true and false that has been rigorously trained to choose what is necessary. For if they possessed it, they would obey the divine Scriptures.