But we speak the wisdom of God in a mystery, the hidden wisdom which God ordained before the ages for our glory.
— 1 Corinthians 2:7
Jesus Christ and Him crucified is the center of Christianity. The very heart of the mystery of Christian redemption is this: That He who is the spotless, sinless Son of God, become sin for us on the Cross. He who knew no sin became sin. Christ bore our sins in His own body on the tree—that is the essence of the Christian mystery.
In His Passion, Jesus suffered not only physically, but spiritually. Now, for the first time in His life, for the first time in history, for the first time in eternity, in some mysterious, inexplicable way, the very tri-unity of God is wrenched apart and Christ is abandoned by His Father. He would cry, “My God, my God, why have You forsaken Me?” (Mark 15:34). He is more alone than any person in all the history of the world has ever been—abandoned by God whose pure eyes could not look upon sin, even when that sin is in His beloved Son. For Jesus Christ became on that day, on that Cross, “sin.”
The mystery of the atonement is that the death of the Son of God made it possible for ordinary people to receive forgiveness and to become right with God. We can never understand it. We can only stand in awe of it and with thankful hearts believe it.