Every Christmas, we commemorate the birth of Christ. Often this means that sentimental visions of nativity scenes, and songs about silent nights and the little Lord Jesus in his manger, dance in our heads. But the birth of Jesus was just the starting point in his earthly ministry. At Christmas, we celebrate not merely his birth, but his Incarnation: as the apostle John wrote, "the Word became flesh and dwelt among us" (John 1:14). The Incarnation—God becoming a man—is the basis of the theology of the New Testament.
The Incarnation brings God close to us
Matthew wrote that the virgin birth was to "fulfill what the Lord had spoken by the prophet: 'Behold, the virgin shall conceive and bear a son, and they shall call his name Immanuel' (which means, God with us)" (Matt. 1:22-23). What the prophet Isaiah wrote symbolically, eight centuries earlier, actually happened at the dawn of the first century: Jesus Christ is, literally, "God with us."
God being made flesh in the person of Jesus means that he is not a disinterested spectator viewing human suffering from afar. The Creator actually entered into his own creation and participated in humanity along with the rest of us, along with our sufferings and temptations. The author of Hebrews writes, "Since therefore the children share in flesh and blood, he himself likewise partook of the same things. . . . For because he himself has suffered when tempted, He is able to help those who are being tempted" (Heb. 2:14). Jesus was baptized by John, not because he needed ritual purification, as he was sinless, but to "fulfill all righteousness" (Matt. 3:15). He did it to identify with us, because we do need to be purified.
The Incarnation shows us God's character
In Jesus' teaching, we see God's teaching. In his miracles, we see God's power. Jesus said that he never did anything of his own initiative; it was his Father doing his own work through him. If you want to see God&'s compassion, see Jesus' healing miracles. If you want to see God's judgment, see Jesus' rebuke of the hypocritical Pharisees. If you want to see divine love, see the way Jesus loved sinners. To see what God is like, just look at Jesus.
The Incarnation shows Jesus' true humanity
As evangelical Christians, we do not compromise on the doctrine of the deity of Christ. He was no mere philosopher or great teacher; he was God in human form. The miracle of the virgin birth shows his divinity: he was not born of ordinary human parents.
Unfortunately, we often over-emphasize Jesus' divinity at the expense of his humanity. There is a surprising and unsettling tendency in some conservative churches to downplay or deny that Mary was the mother of Jesus in a meaningful sense. (I've actually heard some people claim that Mary was merely an "incubator" for his human body.) Likely, they are reacting against Roman Catholic claims concerning Mary as the "mother of God"—which, properly understood, is an affirmation of Christ's deity, not of Mary's exalted status. In rightly rejecting one extreme, some evangelicals have gone too far and embraced another.
The virgin birth shows Jesus' humanity as well as his deity. The New Testament gives us two genealogies of Jesus (Matt. 1:1-17; Luke 3:23-38). It is generally assumed that one of them traces his line through Mary. If so, then Jesus is not merely an avatar of God come to earth in a human body. He is truly a Son of Adam, and a genuine member of the human race.
The Incarnation makes Jesus a perfect priest
A priest is a person who is appointed to mediate for his people in religious services. In the Mosaic covenant, the priestly functions were carried out by the descendants of Moses' brother Aaron. They carried out the animal sacrifices in the temple of Yahweh, which were intended to forgive the sins of the Israelites. The high priest alone was permitted to enter into the Holiest of Holies, the innermost sanctuary of the temple that originally housed the Ark of the Covenant, which was associated with the presence of God. The priest would sprinkle sacrificial blood on the mercy seat that covered the Ark once a year, on the Day of Atonement.
Jesus was not a Levite or a descendant of Aaron, so he was not qualified to be an Aaronic priest. The author of Hebrews describes him instead as a priest "after the order of Melchizedek." Melchizedek is a rather obscure figure from the Old Testament, described as the "king of Salem" and a "priest of God Most High" (Genesis 14:18). Following a battle in which Abraham rescued his nephew Lot who had been abducted, Melchizedek brought Abraham bread and wine and also received a tenth of the spoils as tribute.
The reasoning of Hebrews goes like this: Since Abraham paid tribute to Melchizedek and received a blessing from him, Melchizedek is superior to Abraham, and also Abraham's descendants, the Levitical priests (Heb. 7:4-10). The author also notes that Melchizedek has no recorded genealogy: "neither beginning of days nor end of life" (Heb. 7:3). He resembles Christ, who, being God, has existed from all eternity and lives forever.
Therefore, Christ is a far greater priest than Aaron and his children: not because of his family line, but because he has always been. And because he is tied to Melchizedek and not to Aaron, he is not a Jewish priest for the Jewish people, but one who can intercede before God for all of humanity. Unlike the Aaronic priests, he does not die and need to be replaced, and has no need to offer sacrifices for his own sins first. "Consequently, he is able to save to the uttermost those who draw near to God through him, since he always lives to make intercession for them" (Heb. 7:25).
The Incarnation makes Jesus a perfect Saviour
The sacrificial system of the Mosaic law taught two important lessons. First, forgiveness was available for sin. Second, to receive forgiveness, something had to die. The flaw in the Mosaic system was that the blood shed by an animal could never take away sins completely, so the rituals had to be repeated, time after time, year after year.
But this flaw was by design. The sacrificial system was a foreshadowing of the coming of the Messiah. It was never meant to be an end in itself. As a true man, Jesus Christ is the substitute for humanity that no animal could ever be. As the sinless and perfectly obedient God-man, he had no guilt of his own to make him worthy of execution on the cross. The sin of guilty people was imputed to him, and his righteousness is imputed to them in return. As a perfect priest, he is able to approach God his Father with the perfect sacrifice of his own blood, and through his intercession obtains forgiveness for his people, the church. "For by a single offering he has perfected for all time those who are being sanctified" (Heb. 10:14).
When we grasp the importance of the Incarnation, we can truly appreciate the full weight of the meaning of the words announced by angels to the shepherds on that first Christmas night: "Unto you is born this day in the city of David a Savior, who is Christ the Lord" (Luke 2:11).