John Chrysostom, on 1Cor 1:26

Again; he proved at the same time that the thing is not new, but ancient, as it was presignified and foretold from the beginning. For, "It is written," saith he, "I will destroy the wisdom of the wise." Withal he shews that it was neither inexpedient nor unaccountable for things to take this course: (for, "seeing that in the wisdom of God the world," saith he, "knew not God, God was well pleased through the foolishness of preaching to save them which believe:") and that the Cross is a demonstration of ineffable power and wisdom, and that the foolishness of God is far mightier than the wisdom of man. And this again he proves not by means of the teachers, but by means of the disciples themselves. For, "Behold your calling," saith he: that not only teachers of an untrained sort, but disciples also of the like class, were objects of His choice; that He chose "not many wise men" (that is his word) "according to the flesh." And so that of which he is speaking is proved to surpass both in strength and wisdom, in that it convinces both the many and the unwise: it being extremely hard to convince an ignorant person, especially when the discourse is concerning great and necessary things. However, they did work conviction. And of this he calls the Corinthians themselves as witnesses. For, "behold your calling, brethren," saith he: consider; examine: for that doctrines so wise, yea, wiser than all, should be received by ordinary men, testifies the greatest wisdom in the teacher.

But what means, "according to the flesh?" According to what is in sight; according to the life that now is; according to the discipline of the Gentiles. Then, lest he should seem to be at variance with himself, (for he had convinced both the Proconsul, and other wise men, too, we have seen coming over to the Gospel;) he said not, No wise man, but, "Not many wise men." For he did not designedly call the ignorant and pass by the wise, but these also he received, yet the others in much larger number. And why? Because the wise man according to the flesh will not cast away his corrupt doctrine. And as in the case of a physician who might wish to teach certain persons the secrets of his art, those who know a few things, having a bad and perverse mode of practicing the art which they make a point of retaining, would not endure to learn quietly, but they who knew nothing would most readily embrace what was said: even so it was here. The unlearned were more open to conviction, for they were free from the extreme madness of accounting themselves wise. For indeed the excess of folly is in these more than any, these, I say, who commit unto reasoning things which cannot be ascertained except by faith. Thus, suppose the smith by means of the tongs drawing out the red-hot iron; if any one should insist on doing it with his hand, we should vote him guilty of extreme folly: so in like manner the philosophers who insisted on finding out these things for themselves disparaged the faith. And it was owing to this that they found none of the things they sought for.

"Not many mighty, not many noble;" for these also are filled with pride. And nothing is so useless towards an accurate knowledge of God as arrogance, and being nailed down to wealth: for these dispose a man to admire things present, and make no account of the future; and they stop up the ears through the multitude of cares: but "the foolish things of the world God chose:" which thing is the person one meets in the market more of a philosopher than themselves. Wherefore also he said himself, "That He might put to shame the wise." And not in this instance alone hath he done this, also in the case of the other advantages of life. For, to proceed, "the weak things" He chose; not foolish sons only, but needy also, and contemptible and obscure He called, that He might humble those who were in high places.