Anyway, it starts with "The Need for a Mediator":
Man is in a fallen and sinful condition (Rom. 3). He is under God’s condemnation, and his sin has separated him from his Maker (Rom. 1–2). ...God’s attitude toward mankind is no longer one of indiscriminating affection. Therefore a mediator is necessary if God is to be placated and if man is to be induced and enabled to turn from his sin to God. ...If fallen man is to be restored to God’s favor, a mediator MUST be provided, because of God’s very nature. Human sin has so offended
and insulted all of God’s glorious perfections, that He MUST be repulsed at it. Everything God is, is against human sin. Everything sin is, is against the holy God. (6)
The Bible makes absolutely clear that the Lord Jesus Christ of Nazareth is the one and only Mediator between God and men (1 Tim. 2:5). He alone can be that divinely appointed Mediator for two reasons: (1) Only He possesses all the divinely appointed and divinely prophesied traits of that Mediator; and (2) The time has already passed for the Messiah promised in the Old Testament to make His
appearance. (9)
Furthermore, Jesus of Nazareth was the Mediator-Messiah, because of the “fullness of time” in which He lived (Gal. 4:4). The promised Messiah of the Old Testament must have already come, because the time has passed for His coming (Gen. 49:10; Dan. 9:24–27). He was to come while the second Temple in Jerusalem was standing (Hag. 2:6f; Mal. 3:1f), while the Jewish state was still intact (Gen.
49:10), and while Jerusalem was still the capital of the Jewish theocracy (Hag. 2:6f; Isa. 2:3; Isa. 62:1). (10)
His most definitive name and title is THE LORD JESUS CHRIST (Acts 11:17; 28:31; 15:26; 20:21). ...The title “Lord” (kurios in Greek), is applied to God in the Greek
Old Testament and is the equivalent of “Jehovah.” To call Jesus, “Lord,” is to confess Him to be Jehovah incarnate (John 1:14), and to confess that His authority is exalted and supreme (Mark 12:36f; Luke 2:11; 3:4; Acts 2:36; 1 Cor. 12:3; Phil. 2:11). (11)
The name “Jesus” means “Savior.” It is the Greek form of the Hebrew word for “Joshua,” which is derived from two words meaning “Jehovah is our salvation.” (11)
The name, “Christ,” means “the anointed One.”...It points us to the fact that God has appointed and commissioned Jesus to save His people as their Mediator; and that He has fully equipped Him with the Holy Spirit beyond measure to carry out the offices of prophet, priest and king (John 3:34; Ps. 45:7, John 6:27; Matt. 28:18). (12)
Having established that we need a mediator and that Christ is that mediator, Dr. Morecraft turns us to a more in-depth look at the person of Christ.
Jesus is fully God and fully man in one person forever, or as the Shorter Catechism says, “God and man in two distinct natures and one person, for ever” (WSC, Q. 21)....The “Word,” who is the Son of God, equal to God, and “of the same substance” with God, came to possess a fully human personality, intellect, soul and body, in addition to His divine being and perfections, which remained unchanged. When we speak of the divine nature of Jesus as being “one substance” with God, and of His human nature as being “of her [Mary’s] substance,” we are saying that Jesus from His conception was really and truly a human being, possessing all the properties of man, making Him fully human; and that He possessed all the perfections of God, (who is His perfections), making Him truly and fully God. Whatever can be said of God can be said about Jesus, and whatever can be said about man can be said about Jesus, except that He was and is sinless....although these two natures are united in one person, yet each retains its respective properties or perfections.(15-16)
Jesus is God. This is the emphatic and unequivocal testimony of the entire Bible. (17)
First, the Bible gives Jesus names and titles that belong to God alone. He is actually called “God” and “the Son of God” over forty times in the New Testament....In Titus 2:13, we are told to look forward to “the blessed hope and the appearing of the glory of our great God and Savior, Christ Jesus.” And Jesus Himself said, “I am the Son of God” ( John 10:36).
Second, the Bible attributes to Jesus perfections that belong to God alone.
Third, the Bible records the words of Jesus which only God can speak. Only God can forgive sins (Mark 2:7), and yet Jesus can say, “My son, your sins are forgiven” (Mark 2:5). Exodus 20 says that the Sabbath is to be sanctified unto Jehovah alone; but Jesus says that He is “the Lord of the Sabbath” (Mark 2:28).
Fourth, the Bible ascribes works and activities to Jesus which only God Himself can perform. Christ is the Creator of the universe. Speaking of Him, the apostle John wrote: “All things were made by Him and without Him was not anything made that was made” (John 1:3).
Fifth, the Bible says that we are to give to Jesus Christ the worship and reverence that belong to God alone. Throughout the Bible we are strictly forbidden to worship any mere man, and yet we are commanded to worship Christ, the Son of God. (17-20)
(1) His deity kept His humanity from sinking into oblivion under the weight and full force of the infinite wrath of God and the power of death (Acts 2:24f)....human nature united to the divine nature, as in Jesus, would not sink under the weight of
wrath, for if it did sink, “then it would have been said, that he who is a divine Person, miscarried in an important work which he undertook to perform in his human nature, which would have been a dishonour to him.” 18
(2) His deity gave infinite value and eternal effectiveness to His redeeming work as a man in our behalf (Acts 20:28; Heb. 9:14). If the Mediator were only human, sinless though He might be, and although His actions and sufferings were perfect, yet, being a finite creation, nothing He did could be of the infinite value demanded by God’s justice....The Mediator must obey all the demands of God’s Law in such a way that that law is fully honored; therefore the required obedience must not only be sinless, it must be of infinite worth.
(3) As God, Jesus was able to give His Holy Spirit to His people.
(4) Only as Almighty God incarnate could our Mediator conquer all our enemies...
(5) If Christ is to bring His chosen people to everlasting salvation, He must be God....This is all a truly divine work, therefore, He who performs it must be a divine Person.
(6) It is essential that our Mediator, Jesus Christ, should be God, because the everlasting happiness of His people consists in their enjoyment of Him. He not only is the producer of their eternal blessedness, He is the very heart of it.
A seventh reason is that Jesus, our Mediator, had to be God in order to live, even in death, and to give life to those who were dead. No mere man can voluntarily lay down his life in death, and then take it back again....He said, “I lay down My life that I may take it again. No one has taken it away from Me, but I lay it down on My own initiative. I have authority to lay it down and I have authority to take it up
again” (John 10:17f).
18. Ridgeley, Commentary on the Larger Catechism, 1:484. (20-22)
While remaining no less than God, in possession of all that makes God God, Jesus was, and is, at the same time, really man, possessing all that makes man man. Christ has a true physical body....Being fully human, Jesus had a rational soul. He was not merely half-human and half-divine....As a child, He “increased in wisdom and stature” (Luke 2:52), i.e., intellectually, spiritually and physically. (24)
“It belongs to the truth of our Lord’s humanity, that He was subject to all sinless human emotions.” 24. Benjamin Warfield, The Person and Work of Christ, ed. by Samuel G. Craig (Philadelphia, PA: Presbyterian and Reformed, 1950), 93. (24)
Jesus was neither remote and cold, nor was He dominated by uncontrolled human
emotions. He was warm, personal, and in total emotional control. But the fact that He experienced the whole range of human emotions is testimony to His true humanity. (25)
To be our Savior, Jesus, the Son of God, identified Himself completely with mankind, which involved the assumption of flesh and blood, as well as all human feelings, sensibilities and frailties. By this incarnation He was fully qualified to be our High Priest and our substitutionary sacrifice, turning away God’s wrath from us. Representation and substitution require identification. (25)
(1) It was necessary for the Mediator to be human “that He might advance our nature.” The greatest honor and dignity to which human nature could be advanced is to be taken into an inseparable union with the Second Person in the Holy Trinity.
(2) It was necessary for the Mediator to be human “that He might… perform obedience to the Law” (Gal. 4:4)....The Law not only demanded punishment for sin, it also demanded perfect obedience from man. Therefore, the obedience of the Mediator had to be performed by a man.
3) It was necessary for the Mediator to be human “that He might… make intercession for us in our nature” (Heb. 2:14; 7:24, 25). God does not make intercession, for intercession includes worship, and presupposes dependence, which is inconsistent with God’s self-sufficiency and independence. Intercession
is prayer, and only men pray. Therefore, Christ’s making intercession for us is possible because of and the necessary result of His incarnation.
(4) It was necessary for the Mediator to be human “that He might… have a fellow-feeling [sympathy] of our infirmities.”...As the omniscient God, the Mediator has a perfect knowledge of our weaknesses, but not an “experiential knowledge” of them. Only a human being can actually experience weaknesses in his life, having passions and emotions.
(5) It was necessary for the Mediator to be human “that we might receive the adoption of sons, and have comfort and access with boldness unto the throne of grace.” Galatians 4:4–5 makes clear that the Son of God became incarnate to
redeem His people “that we might receive the adoption of sons.”
Since man had sinned against God, man must bear the spiritual and physical penalty for that sin (John 12:27; Acts 3:18; Heb. 2:14; 9:22).
(26-28)
The humanity of Jesus Christ never had a separate existence or personality of its own; but from its conception in the womb of Mary, it was united to the second Person of the Trinity, God the Son. This is an intimate, eternal and inseparable union, yet the two natures are not confused, and each retains its own essential human characteristics and divine perfections....To say that the Word became flesh is not to say that the second Person of the Trinity ceased to be God. It is to say that the second Person of the Trinity came to possess human characteristics in addition to His divine perfections, which remained unchanged. God became man in Christ, not by changing Himself into man; but by uniting Himself with man’s nature. (29)
In the incarnation of Christ, the union of the divine Person with the human nature constituted one single person, “which person is very God, and very man, yet one Christ,”(WCF, VIII, ii)....His single, theanthropic (divine-human) personality was not even dissolved in His death. Between His death and resurrection, His physical body and His human soul, although separated in death, were still united with His divine nature. (29)
To be effective in His work as Mediator, Jesus Christ was and is altogether free from sin. (31)
He had to be human so He could actually die. He had to be God so He could continue to live and give infinite value to His death. (31)
In order to reconcile us to God, the works of each nature in Christ must be accepted by God as the works of the whole person....Furthermore, the works of each nature of Christ are to be relied on by believers as the works of the whole divine-human Person of Christ. (33)