Vincent's NT Word Studies
21. After that (epeidh). Rev., correctly, seeing that.By wisdom (dia thv sofiav). Better, as Rev., giving the force of the article, "through its wisdom."
Preaching (khrugmatov). Not the act, but the substance of preaching. Compare ver. 23.
To save (swsai). The word was technically used in the Old Testament of deliverance at the Messiah's coming; of salvation from the penalties of the messianic judgment, or from the evils which obstruct the messianic deliverance. See Joel ii. 32; Matt. i. 21; compare Acts ii. 40. Paul uses it in the ethical sense, to make one a partaker of the salvation which is through Christ. Edwards calls attention to the foregleam of this christian conception of the word in the closing paragraph of Plato's "Republic:" "And thus, Glaucon, the tale has been saved, and has not perished, and will save (swseien) us if we are obedient to the word spoken, and we shall pass safely over the river of forgetfulness and our soul will not be defiled."
Robertson's NT Word Studies
1:21 {Seeing that} (epeide). Since (epei and d) with explanatory gar. {Through its wisdom} (dia tes sofias). Article here as possessive. The two wisdoms contrasted. {Knew not God} (ouk egnw). Failed to know, second aorist (effective) active indicative of ginwskw, solemn dirge of doom on both Greek philosophy and Jewish theology that failed to know God. Has modern philosophy done better? There is today even a godless theology (Humanism). "Now that God's wisdom has reduced the self-wise world to ignorance" (Findlay). {Through the foolishness of the preaching} (dia tes mwrias tou kerugmatos). Perhaps "proclamation" is the idea, for it is not keruxis, the act of heralding, but kerugma, the message heralded or the proclamation as in verse #23. The metaphor is that of the herald proclaiming the approach of the king (#Mt 3:1; 4:17). See also kerugma in #1Co 2:4; 2Ti 4:17. The proclamation of the Cross seemed foolishness to the wiseacres qen (and now), but it is consummate wisdom, God's wisdom and good-pleasure (eudokesan). The foolishness of preaching is not the preaching of foolishness. {To save them that believe} (swsai tous pisteuontas). this is the heart of God's plan of redemption, the proclamation of salvation for all those who trust Jesus Christ on the basis of his death for sin on the Cross. The mystery-religions all offered salvation by initiation and ritual as the Pharisees did by ceremonialism. Christianity reaches the heart directly by trust in Christ as the Savior. It is God's wisdom.