“Behold, the Lamb of God, who takes away the sin of the world! And I have seen and have borne witness that this is the Son of God.” (John 1:29, 34). And [he]was declared to be the Son of God in power according to the Spirit of holiness by his resurrection from the dead, Jesus Christ our Lord, (Romans 1:4).

 Whoever confesses that Jesus is the Son of God, God abides in him, and he in God. (1 John 4:15).

Since then we have a great high priest who has passed through the heavens, Jesus, the Son of God, let us hold fast our confession.  For we do not have a high priest who is unable to sympathize with our weaknesses, but one who in every respect has been tempted as we are, yet without sin. Let us then with confidence draw near to the throne of grace, that we may receive mercy and find grace to help in time of need. 
(Hebrews 4:14-16).

That Jesus Christ is the Son of God is the most contentious claim in all of history. Therefore, to believe it invites every reaction from joyful acceptance to hateful persecution. Why is it so important that we see that Jesus Christ is the Son of God? Furthermore, how do we come to celebrate this glorious fact?

First, Jesus’ claim to be the Son of God is critical for our redemption. Jesus plays a completely unique role in history, in that he is only one able to stand between humanity and God. In the Old Testament, certain men were chosen to function as priests. Their job was to represent God to the people through teaching and worship, and represent the people back to God, through sacrifice and offerings.

With the coming of Jesus Christ, we’ve been given a truer and better high priest. In Jesus Christ, we find the one person who is fully human, able to represent humanity to God. And, we also find the one person who is fully God, able to truly represent God to us. He is the image of the invisible God, the exact representation of his nature, (Col. 1:15). If Jesus were not the Son of God, then his role as our great high priest wouldn’t be all that great.

But, Jesus is still more. In the Old Testament, the priests would lead God’s people in worship by offering sacrifices for sin. When the people came to the temple, an animal would have to die to cover their iniquity. This is where Jesus is even greater. Jesus didn’t just offer some imperfect sacrifice, hoping it would end the treasonous rebellion against his Father. Jesus offered himself. The Great High Priest became our perfect, infinitely worthy sacrifice.

Because sin has cause an infinite gap to open up between God and humanity, only an sacrifice of limitless worth was able to traverse it. If Jesus were not God the Son—fully God and fully man—then his sacrifice on our behalf would not be fully worthy, and we would be left in our sin.

But how do we know? How can we really be sure that Jesus Christ really is God the Son? The answer: resurrection. You see, the sacrifice that Jesus made was for us. The death he died was not because of his own sin, it was for ours. Scripture tells us that the wages of sin is death, but Jesus had no sin, so not even death had a claim on him. He conquered death on our behalf, so that we, by faith in him, would conquer death too. If Jesus were still in the ground, we wouldn’t be asking if he was the Son of God.

But, Jesus is not still in the ground. He is risen. The Son has ascended to the Father, and the people of God rejoice.