In our study of the biblical doctrines summarized in the Heidelberg Catechism, we have seen how the old covenant saints looked forward to God’s supernatural intervention to save His people (Isa. 7:14). When the Lord did intervene to redeem us, however, He did so in a manner different from His other miraculous works in the history of redemption. His intervention for our salvation was unique, for in order to save us the Son of God became incarnate in the person of Jesus Christ. Our Creator entered into human history and human experience to rescue us.
This was the only way we could be saved. The Son of God had to enter human history and unite to Himself a human nature, the Mediator had to be true God, as the answer to question 17 of the Heidelberg Catechism explains. Why was this the case? First, the nature of God’s love for the world demanded the incarnation. In today’s passage, we read that “God so loved the world” (John 3:16). The Greek word for “so” is houtōs, an intensifying adverb that signifies “in this manner.” Jesus’ point was that God’s love for His creation is such that the highest and clearest way that He could declare this love was for the Son to atone for His people’s sin. God loves the world so deeply, so magnificently, that only giving Himself in the person of His Son could show the extent of His love. This kind of love demanded such a sacrifice.
Furthermore, only a Redeemer who was truly God could bear the weight of sin. One person can hardly suffer the fullness of God’s wrath against his sin and respond appropriately. In fact, unredeemed people in hell continue resisting the Lord even under His wrath. They recognize the justness of their punishment, but they do not love God for His justice, nor do they act logically and stop rebelling against Him. Forever the “evildoer” will “still do evil” and the “filthy” will “still be filthy” (Rev. 22:11). Impenitent sinners will remain unclean, doing “what is detestable or false,” chafing at God’s judgment outside the gates of the New Jerusalem (21:27). If a mere human cannot bear God’s wrath for his sin, how could one bear God’s wrath for the sins of many?
Moreover, would it not be more difficult to bear the Lord’s wrath for many if one were sinless and undeserving of such pain? Yet Jesus did all this because His divinity sustained Him on the cross.
In Cur Deus Homo, Anselm of Canterbury gives another reason why the Mediator must be fully God: “If any other person [except God] were to redeem a man from eternal death, the redeemed man would be rightly judged to be his servant” (chap. 5). If Jesus were merely human, we would be devoting all that we are to a mere man. Because Jesus is God incarnate, we can serve Him wholeheartedly, knowing that we give ourselves entirely to the Lord.