Heidelbasics: Brief Weekly Reflections on the Heidelberg Catechism by Rev. David Fagrey, Pastor of Grace Reformed Church of Rapid City, SD
16. Why must he be a true and righteous man?
Because the justice of God requires that the same human nature which has sinned should make satisfaction for sin; but one who is himself a sinner cannot satisfy for others.
Our Mediator must be a real man, because he that would make satisfaction for man should himself be very man, having sprung from the posterity of Adam, which had sinned (1 Cor. 15:21). And our Mediator must be a perfectly righteous man, for if he himself had been a sinner, he could not have escaped the wrath of God (Isa. 53:11).
17. Why must he also be true God?
That by the power of His Godhead He might bear in His manhood the burden of God’s wrath, and so obtain for and restore to us righteousness and life.
If our Mediator had been only a man, even a sinless man, he would have been crushed under the heavy weight of God’s wrath. It was necessary therefore that our Mediator should possess infinite strength that he might endure in his manhood an infinite punishment. But this he could not have done had he not been God (Acts 20:28).
18. But who now is that Mediator, who in one person is true God and also a true and righteous man?
Our Lord Jesus Christ, who is freely given unto us for complete redemption and righteousness.
The only Mediator between God and man is the God-Man–the LORD Jesus Christ–the eternal Son of God who became a man to reconcile God and man (1 Tim. 2:5; 3:16). The second creation, whereby sinners are made new creatures (1 Cor. 5:17), “was to be effected by the same person through whom the first creation was made [John 1:3]” (Ursinus). In Christ alone we have complete redemption and righteousness. He obeyed God’s law perfectly and He satisfied God’s wrath for our disobedience (1 Cor. 1:29).
19: From where do you know this?
From the Holy Gospel, which God Himself first revealed in Paradise, afterwards proclaimed by the holy patriarchs [Abraham, Isaac, Jacob] and prophets, and foreshadowed by the sacrifices and other ceremonies of the law, and finally fulfilled by His Well-Beloved Son.
From the holy law, we come to know our sin and misery; from the holy Gospel, we come to know our salvation from sin and misery through the Mediator Jesus Christ. The gospel (good news) was first revealed immediately after the Fall: God promised salvation through the Seed, who would be “bruised” (Gen. 3:15). God “preached the gospel to Abraham” (Gal. 3:8), saying: “in your Seed all the nations shall be blessed” (Gen. 22:18). All the blood shed on Jewish altars was a prophecy of the Son of God (the Lamb of God!) offering Himself to God as a sacrifice to be killed in our place. “He was bruised for our iniquities” (Isaiah 53:5). OT believers were saved by faith in the Messiah who would come in the flesh. NT believers are saved by faith in the Messiah who has already “given Himself for us, an offering and sacrifice to God” (Eph. 5:2).