Summary of God's plan
[T]he foolishness of God is wiser than men, and the weakness of God is stronger than men. ...
But God has chosen the foolish things of the world to put to shame the wise, and God has chosen the weak things of the world to put to shame the things which are mighty
The crucifixion of Christ is foolishness to those who are supposedly wise; these will be proven foolish when the Messiah comes in His glory, and for all on their death who do not believe in the Lord Jesus Christ.