Paul had been bred up in Jewish learning; but the plain preaching of a crucified Jesus, was more powerful than all the oratory and philosophy of the heathen world. This is the sum and substance of the gospel. Christ crucified is the foundation of all our hopes, the fountain of all our joys. And by his death we live. The preaching of salvation for lost sinners by the sufferings and death of the Son of God, if explained and faithfully applied, appears foolishness to those in the way to destruction. The sensual, the covetous, the proud, and ambitious, alike see that the gospel opposes their favorite pursuits. But those who receive the gospel, and are enlightened by the Spirit of God, see more of God's wisdom and power in the doctrine of Christ crucified, than in all his other works.
[Matthew Henry]

Romans 1:16 ... For I am not ashamed of the gospel of Christ: for it is the power of God unto salvation to every one that believeth; to the Jew first, and also to the Greek.
Hebrews 4:12 ... For the word of God is quick, and powerful, and sharper than any twoedged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart.
1 Corinthians 1:18 ... For the preaching of the cross is to them that perish foolishness; but unto us which are saved it is the power of God. ❤