11 Tim 2:5; ²Jn 1:1, 14; 10:30; Phil 2:6; ³Gal 4:4; ⁴Lk 1:35; Rom 9:5; Col 2:9; Heb 7:24–25.

A mediator is one who stands between two parties, in order to make or restore peace and friendship. Adam was our representative in the Covenant of Works, but he was not quite our mediator. But with the Fall, man was estranged from God, and a mediator was needed that we may be restored to friendship with God. The terms and condition under which God now relates to man is known as the Covenant of Grace, and the mediator between God and us is the Lord Jesus Christ. So the apostle Paul declares: "For there is one God, and one mediator between God and men, the man Christ Jesus" (1 Tim 2:5). Our catechism, based on this verse, rightly emphasises that Christ is the only Mediator of the Covenant of Grace. This verity immediately and unquestionably invalidates the Romish doctrine that Mary is a co-mediatrix (or co-mediator) and that believers can appeal to her and to departed saints to intercede for them before God.

Our catechism goes on to teach us several other important truths concerning the person of the Lord Jesus Christ.

First, we are taught that He is the eternal Son of God. He did not become the Son of God; He has always been the Son of God, and remains the Son of God, the second person of the Trinity. This is clearly taught in John 1:18—"No man hath seen God at any time; the only begotten Son, which is in the bosom of the Father, he hath declared him" (See also Jn 1:14). The Lord Jesus was, is and continues to be the "only begotten Son" (monogenhv") of the Father.

Secondly, we are taught that the Lord Jesus Christ is "one in substance and equal with the Father." That is to say that although economically or functionally, He is subordinate to His Father in so far as His personhood is concerned, He is, in terms of His substance or being and existence, fully equal in power and glory with the Father. "I and my Father are one" (Jn 10:30), the Lord declares.

What this means is that the Lord Jesus Christ is fully and eternally, self-existent God, which is a doctrine that is denied in many circles today. J.G. Vos has a very insightful summary of this denial:

1. The doctrine of the deity of Christ is denied by those who say that Christ is divine because all men are divine. If all men are divine, then for Christ to be divine is nothing out of the ordinary.
2. The doctrine of the deity of Christ is denied by those who, while calling Christ "the Son of God," still refuse to say that He is of one substance and equal with the Father. Such people consider it a sin to worship Jesus Christ.
3. The doctrine of the deity of Christ is denied by those who accept his deity only as a "limiting concept"; that is when they speak of Christ as divine, or call him "the Son of God," they do not mean that this is really the absolute truth about Christ; they only mean that Christ’s "deity" is a convenient label for classifying Christ for the time being; in calling Christ "God" they do not mean that he really and truly is God, but only that he is "God" for us human beings—that he may occupy the place of God in our human thinking at the present time. It is obvious that the idea of Christ as a "limiting concept" is something very different from the faith of orthodox historic Christianity in Christ’s deity (The Westminster Larger Catechism: a Commentary, [P&R, 2002], 86).

But thirdly, we are taught that the Lord Jesus Christ, "in the fullness of time became man, and so was and continues to be God and man" (see Gal 4:4). That is to say, the Lord Jesus Christ, was God from all eternity, but at an appointed time, He took on human nature so that from that point of time onwards, He was God and man "in two entire distinct natures, and one person, for ever."

Take note of the very careful wordings of our catechism.

• First notice the term ‘entire.’ This means that the human nature of the Lord Jesus Christ is the same as the human nature of all men. He did not only take on a human body but not a human soul. The human nature in its entirety comprises body and soul. The Lord Jesus Christ as we shall see in our next question, has a human body and a human soul. He is not, as commonly misunderstood, a divine Spirit combined with a human body.
• Secondly, note the term ‘distinct.’ This means that the human and divine natures of the Lord Jesus Christ are not mixed. He is fully God, having the fullness and glory of the Godhead at all times; and He is fully Man, having during his earthly sojourn all the limitations of human beings such as growing weary, and thirsty and hungry, and today after His ascension, having all the properties of a glorified, resurrected saint.
• Thirdly, note the phrase ‘one person’. This means that the Lord Jesus Christ was not two persons combined into one as taught by the Nestorians of the 5^th Century. The Lord Jesus Christ has always been a divine person. In His incarnation, He took on human nature, not a human person. Though He has two wills because He has two natures, He is one person. All He does He does as the God-Man, and as such His human will never contradicts His divine will. It is wrong therefore to speak of Christ in His incarnation loving someone in His human nature, but hating him in His divine nature.
• Fourthly, take not of the term ‘forever.’ This teaches us that the Lord Jesus Christ is still fully God and fully Man today. He did not cast away his human nature as some mistakenly think. Indeed, the writer of Hebrews reminds us that it is because the Lord Jesus Christ continues as a man, He continues to be our intercessor and mediator that He may save us to the uttermost (Heb 7:23-25). W