From Martin Hengel:"All this leads to a final conclusion which it is difficult to resist. When Paul spoke in his mission preaching about the 'crucified Christ' (1 Corinthians 1.23; 2.2; Galatians 3.1), every hearer in the Greek-speaking East between Jerusalem and Illyria (Romans 15.19) knew that this 'Christ' - for Paul the title was already a proper name - had suffered a particularly cruel and shameful death, which as a rule was reserved for hardened criminals, rebellious slaves and rebels against the Roman state. That this crucified Jew, Jesus Christ, could truly be a divine being sent on earth, God's Son, the Lord of all and the coming judge of the world, must inevitably have been thought by any educated man to be utter 'madness' and presumptuousness" (83).
This is why it is God's work in saving His own people through the foolishness of the message preached. Otherwise, no one would believe such a scandalous message. But, as Paul says:
1 Corinthians 1:21, 30-31 — For since in the wisdom of God the world through its wisdom did not come to know God, God was well-pleased through the foolishness of the message preached to save those who believe ... But by His doing you are in Christ Jesus, who became to us wisdom from God, and righteousness and sanctification, and redemption, so that, just as it is written, "LET HIM WHO BOASTS, BOAST IN THE LORD."
