The cross is

“Jews demand miraculous signs… but we preach Christ crucified: a stumbling block to Jews…” —1 Corinthians 1:22-23
“Jesus came to that which was his own, but his own did not receive him.” —John 1:11

The cross is

“Greeks look for wisdom… but we preach Christ crucified: …foolishness to Gentiles…” —1 Corinthians 1:22-23
“The secret to a successful society is education. If we can just give everybody a good education, then it must follow that the world will get better and better.” —Socrates

The cross is

“but to those whom God has called, both Jews and Greeks, Christ the power of God and the wisdom of God…” —1 Corinthians 1:24-25
“…and through him to reconcile to himself all things… by making peace through his blood, shed on the cross.” —Colossians 1:19-20
“…He forgave us all our sins… triumphing over them by the cross.” —Colossians 2:13-15
“Salvation is found in no one else, for there is no other name under heaven given to men by which we must be saved.” —Acts 4:12
“…I resolved to know nothing while I was with you except Jesus Christ and him crucified.” —1 Corinthians 2:1-2