Heidelberg Q. 18. But who is that Mediator who at the same time is true God and a true and righteous man?
A. Our Lord Jesus Christ, whom God made our wisdom, our righteousness and sanctification and redemption (I Corinthians 1:30).

Heidelberg Q. 19. From where do you know this?
A. From the holy gospel, which God Himself first revealed in Paradise. Later, He had it proclaimed by the patriarchs and prophets, and foreshadowed by the sacrifices and other ceremonies of the law. Finally, He had it fulfilled through His only Son.