1 Corinthians 1:21

For after that in the wisdom of God
These words contain a reason proving the infatuation of men, with respect to "the wisdom of God"; by which may be meant either Christ, who is the wisdom of God, was in the world, and yet the world of the Jews, and their chief Rabbins among them, with all their wisdom, neither knew him, nor God his Father; or the Gospel, which is also so called, and though this was come, both into the Jewish and Gentile world, yet neither of them, by their natural wisdom, knew the God of grace, so manifestly revealed in it; or rather the works of creation, in which there is such a visible display of the wisdom of God: yet "the world by wisdom knew not God"; the author of them: the Gentiles knew him not in any spiritual and saving manner, as in Christ, or the God of all grace; yea, they knew him not as the God of nature to be the one, only, true God; they knew him not so as to glorify him as God, or to worship him in a right way and manner: wherefore,

it pleased God by the foolishness of preaching to save them that
believe;
it was his purpose and decree within himself; it was his sovereign good will and pleasure; it was what he, without any motion from, or merit in the creature, resolved of himself from all eternity that he would "save", not the wise man, the Scribe, the disputer of this world, the rationalist, the talker, nor the worker, but "them that believe" in his Son; that look unto him, venture on him, and commit the care and keeping of their souls to him, however weak, mean, and despicable they may otherwise be; or whether they believe with a weak, or a strong faith, so be it, it is but true: the Ethiopic version reads, "that believe in this foolish doctrine"; and this he determined to do, and did, "by the foolishness of preaching"; or by that sort of preaching, which both for the matter of it, Christ, that itself, and the manner of it, the world reckons foolishness; and which are the things of the Father's grace in election, of the Son's grace in redemption, and the Spirit's in regeneration: so the wise men of the world, with all their wisdom, are left ignorant of God, and perish in their sins, whilst the Gospel they despise is the power of God unto salvation to all that believe in Christ; this, through efficacious grace, becomes the means of regenerating and quickening men, showing them their need of salvation, and where it is, and of working faith in them to look to Christ for it.