Westminster Larger Catechism in modern English question number thirty-six:
Q. 36. Who is the Mediator of the Covenant of Grace?
A. The only Mediator of the Covenant of Grace is the Lord Jesus Christ, the eternal Son of God. He is of one substance and equal with the Father, yet he became a man in the fullness of time. Thus he was and continues to be God and man, one person in two entirely distinct natures, forever.