1 Corinthians 3:18

"Let no man deceive himself." This also is in reference to that person, as thinking himself to be somewhat and flattering himself on wisdom. But that he might not seem to press on him at great length in a mere digression; he first throws him into a kind of agony and delivers him over unto fear, and then brings back his discourse to the common fault, saying, "If any man among you seemeth to be wise in this world, let him become a fool, that he may become wise." And this he doth afterwards with great boldness of speech, as having sufficiently beaten them down, and shaken with that fear the mind not of that unclean person only, but of all the hearers also: so accurately does he measure the reach of what he has to say. For what if a man be rich, what if he be noble; he is viler than all the vile, when made captive by sin. For as if a man were a king and enslaved to barbarians, he is of all men most wretched, so also is it in regard to sin: since sin is a barbarian, and the soul which hath been once taken captive she knoweth not how to spare, but plays the tyrant to the ruin of all those who admit her.

"Let no man deceive himself; if any man thinketh that he is wise in this world, let him become a fool." As he bids one become, as it were, dead unto the world;-and this deadness harms not at all, but rather profits, being made a cause of life:-so also he bids him become foolish unto this world, introducing to us hereby the true wisdom. Now he becomes a fool unto the world, who slights the wisdom from without, and is persuaded that it contributes nothing towards his comprehension of the faith. As then that poverty which is according to God is the cause of wealth, and lowliness, of exaltation, and to despise glory is the cause of glory; so also the becoming a fool maketh a man wiser than all. For all, with us, goes by contraries. Further: why said he not, "Let him put off wisdom," but, "Let him become a fool?" That he might most exceedingly disparage the heathen instruction. For it was not the same thing to say, "Lay aside thy wisdom," and, "become a fool." And besides, he is also training people not to be ashamed at the want of refinement among us; for he quite laughs to scorn all heathen things. And for the same sort of reason he shrinks not from the names, trusting as he does to the power of the things which he speaks of. Wherefore, as the Cross, though counted ignominious, became the author of innumerable blessings, and the foundation and root of glory unspeakable; so also that which was accounted to be foolishness became unto us the cause of wisdom. For as he who hath learned anything ill, unless he put away the whole, and make his soul level and clear, and so offer it to him who is to write on it, will know no wholesome truth for certain; so also in regard of the wisdom from without. Unless thou turn out the whole and sweep thy mind clear, and like one that is ignorant yield up thyself unto the faith, thou wilt know accurately nothing excellent. For so those also who see imperfectly if they will not shut their eyes and commit themselves unto others, but will be trusting their own matters to their own faulty eyesight, they will commit many more mistakes than those who see not. But how, you will say, are men to put off this wisdom? By not acting on its precepts.