Why Must Jesus Be God and Man?

In the beginning was the Word, and the Word was with God, and the Word was God. The Word became flesh and made his dwelling among us (John 1:1, 14).
Winston Churchill once described Russia as “a riddle, wrapped in a mystery, inside an enigma.” One could use the same phrase to describe the how and why of the dual nature of Jesus—God and man in one person.
“True God and true man” is a teaching that has been a challenge to human logic for generations. One example: When Jesus died on the cross, did God die? The answer: When Jesus died, it was the true God and true man—the one person—Jesus, who died. Thus the Good Friday hymn states, “O sorrow dread! Our God is dead” (ELH 332:2).
But why is the incarnation, “the Word becomes flesh,” essential for our redemption? God’s Word states: “Since the children have flesh and blood, he too shared in their humanity so that by his death he might destroy him who holds the power of death… For this reason he had to be made like his brothers in every way, in order that he might become a merciful and faithful high priest in service to God, and that he might make atonement for the sins of the people” (Hebrews 2:14, 17).
Simply put, Christ had to be truly human to be a valid substitute for the payment of sin and a righteous life. Jesus had to be truly God to make this payment and righteous life supernaturally cover all mankind from creation to Judgment Day.
The Bible gives us another reason for Christ’s dual nature: “For we do not have a high priest who is unable to sympathize with our weaknesses, but we have one who has been tempted in every way, just as we are—yet was without sin” (Hebrews 4:15). We have someone who understands us and can truly give us real answers to our real problems because He really is one of us.
The following story (in a different version) was made famous by radio personality Paul Harvey and drives home this need to be the man/God that makes Jesus our perfect Savior.
There was a man who didn’t believe in God. One Christmas Eve, the little church his wife and daughter attended was having a special program. “Daddy, won’t you please celebrate Christmas with us?” his daughter begged. “Sorry, little one, I’m busy,” he responded. Watching them leave, he thought, “Why would God leave heaven and become human? Christmas and God don’t make sense.” He turned on the TV. The weatherman announced that a snow storm was hitting their county. A few hours passed and he heard a noise—a pecking on the window pane. Small birds were hitting the glass, trying to escape the snow and extreme cold. The man was moved with compassion. He thought about how he could help the little birds. He knew his barn would be warm, and the birds could ride out the storm in the barn. Quickly, he put on his coat and made his way to the barn. He opened the huge barn doors and began to try to shoo the birds from the window into the barn. He tried and he tried, but the birds flew back to the window. He thought, “If only I could become a bird, then I could lead them into the barn and out of harm’s way. We are like the birds. So you became like us to save us. Now I understand.”
How Jesus can be both the infinite God and finite man, how the eternal God can participate in Jesus’ death, how the He who was dead now lives—these truly are mysteries inside an enigma. But these mysteries about Jesus are the central truths of our salvation. Jesus must be true God and Man to be our Mediator and our Savior.
Jeff Londgren is pastor of Trinity Lutheran Church in Rogers City, Michigan.