1 Paul, called to be an apostle of Jesus Christ through the will of God, and Sosthenes our brother,
2 To the church of God which is at Corinth, to those who are sanctified in Christ Jesus, called to be saints, with all who in every place call upon the name of Jesus Christ our Lord—both theirs and ours:
3 Grace to you, and peace from God our Father and from the Lord Jesus Christ.
4 I thank my God always on your behalf for the grace of God which is given to you by Jesus Christ, 5 That in everything you are enriched by him, in all utterance and in all knowledge, 6 Even as the testimony of Christ was confirmed in you, 7 So that you are not lacking in any gift, waiting for the coming of our Lord Jesus Christ, 8 Who will also confirm you to the end so that you may be blameless in the day of our Lord Jesus Christ. 9 God is faithful, by whom you were called to the fellowship of his Son Jesus Christ our Lord.
10 Now I implore you, brothers, by the name of our Lord Jesus Christ, that you all speak the same thing and that there be no divisions among you, but that you be perfectly joined together in the same mind and in the same judgment. 11 For it has been declared to me concerning you, my brothers, by those who are of the house of Chloe, that there are contentions among you. 12 Now this I say, that each of you says, "I am of Paul," "I of Apollos," "I of Cephas," and, "I of Christ." 13 Is Christ divided? Was Paul crucified for you? Or were you baptized in the name of Paul? 14 I thank God that I baptized none of you except Crispus and Gaius, 15 Lest any should say that I had baptized in my own name. 16 And I also baptized the household of Stephanas. Besides them, I do not know whether I baptized any other. 17 For Christ has not sent me to baptize, but to preach the gospel, not with wisdom of words, lest the cross of Christ should be made of no effect.
18 For the preaching of the cross is foolishness to those who perish. But to us who are saved, it is the power of God.
19 For it is written, "I will destroy the wisdom of the wise and will bring to nothing the understanding of the prudent."
20 Where is the wise? Where is the scribe? Where is the disputer of this world? Has God not made the wisdom of this world foolish? 21 For since, in the wisdom of God, the world by wisdom did not know God, it pleased God by the foolishness of preaching to save those who believe. 22 For the Jews require a sign and the Greeks seek wisdom, 23 But we preach Christ crucified, to the Jews a stumbling-block and to the Greeks foolishness, 24 But to those who are called, both Jews and Greeks, Christ the power of God and the wisdom of God. 25 For the foolishness of God is wiser than men, and the weakness of God is stronger than men.
26 For you see your calling, brothers, that not many wise men after the flesh, not many mighty, not many noble are called. 27 But God has chosen the foolish things of the world to confound the wise, and God has chosen the weak things of the world to confound the things which are mighty, 28 And God has chosen the base things of the world, the things which are despised, and the things which are not, to bring to nothing the things that are, 29 So that no flesh should glory in his presence. 30 But of him you are in Christ Jesus, who, from God, is made to us wisdom, righteousness, sanctification, and redemption, 31 So that, according as it is written, "He who glories, let him glory in the Lord."
[v.19] - Quoting Isaiah 29:14 (LXX—paraphrased). See also, Obadiah 1:8.
[v.31] - Quoting Jeremiah 9:24 (paraphrased). From John Calvin's Commentary: "This is also more clearly apparent from the context in the writings of the Prophet, from whom Paul has borrowed this testimony; for in that passage the Lord, after stripping all mankind of glory in respect of strength, wisdom, and riches, commands us to glory only in knowing him, (Jeremiah 9:23-24.)"