At the very heart of the Christian faith we find the doctrine of the Incarnation–Jesus Christ, the second person of the Holy Trinity and the eternal son of God took to himself a true human nature for the purpose of saving us from our sins. It is this doctrine which marks Christianity off as a supernatural religion, grounded in specific truth claims–i.e., God was in Christ reconciling the world to himself (cf. 2 Corinthians 5:18)–and which aims not for the moral improvement, enlightenment, or personal benefit of its adherents, but for the salvation of all those sinners whom God has chosen to save in Jesus Christ.
The incarnation of Jesus Christ is the proof that God keeps his promises. This event is the key turning point in what is truly the greatest story ever told. At the dawn of human history, God placed Adam in Eden and commanded him not to eat from the tree of the knowledge of good and evil. But Adam ate from the forbidden tree, plunging the entire human race into sin and death. But even as God was pronouncing the curse upon Adam, Eve, and the serpent (cf. Genesis 3), God promised to rescue Adam from his sin through the seed of the woman–that is, through a biological descendant from Eve who will redeem God’s people from their sin (Genesis 3:15). It will take a second Adam–one who obeys the covenant of works which Adam broke and who alone can redeem us from the guilt and power of sin–to undo the consequences brought upon us by the first Adam. And this brings us to the incarnation of Jesus Christ, the person in whom God fulfills his promises and who is our Immanuel (God with us). The Word must become flesh if any of us are to be saved from the havoc wrought upon us by the first Adam (cf. John 1:17). There is no other way.
The Old Testament is filled with various messianic prophecies, in which God’s promise to redeem his people are set forth with an amazing specificity. In fact, there are some sixty-one major messianic prophecies regarding the coming of Jesus Christ found throughout the Old Testament, all of which are explicitly fulfilled by the coming of Jesus Christ in human flesh as detailed in throughout New Testament. We have already seen that God’s promise to Adam and Eve in Genesis 3:15 is fulfilled when Jesus dies upon the cross. Jesus not only crushes Satan, but suffers for his people to bring about their redemption. As but one additional illustration of God’s redemptive promises being fulfilled in Christ, in Isaiah 7:14 we find this amazing prophecy: “Therefore the Lord himself will give you a sign. Behold, the virgin shall conceive and bear a son, and shall call his name Immanuel.” The coming one is not only supernaturally conceived, he will be God in human flesh. This is why the Old Testament perspective on redemption is one of longing, anticipation, expectation, and hope.
When we come to the New Testament era, we immediately discover that something very dramatic and completely beyond all human expectation is taking place. In Matthew’s gospel, we find the historical record of the fulfillment of a number of these ancient messianic prophecies. In Matthew 1:18-23, we read these words: “Now the birth of Jesus Christ took place in this way. When his mother Mary had been betrothed to Joseph, before they came together she was found to be with child from the Holy Spirit. And her husband Joseph, being a just man and unwilling to put her to shame, resolved to divorce her quietly. But as he considered these things, behold, an angel of the Lord appeared to him in a dream, saying, `Joseph, son of David, do not fear to take Mary as your wife, for that which is conceived in her is from the Holy Spirit. She will bear a son, and you shall call his name Jesus, for he will save his people from their sins.’ All this took place 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).”
In the supernatural conception and birth of Jesus Christ, God fulfills his promise to Adam to send the seed of the woman who will crush the head of the serpent. But the birth of Jesus Christ also fulfills the promise God made to Abraham, to bless the world through one his biological descendants (Genesis 22:15-18). This explains why the gospel of Matthew opens with a genealogical record, which traces our Lord’s ancestry back to Abraham through the line of Judah and the house of David. God keeps his promises, and our Lord’s genealogy chart is the proof.
Why did God send his eternal son, and what does this mean for us? While the mechanics of the incarnation largely remain a mystery–in fact, Paul speaks of the incarnation in 1 Timothy 3:16 as such, “great indeed, we confess, is the mystery of godliness: [Jesus] was manifested in the flesh, vindicated by the Spirit, seen by angels, proclaimed among the nations, believed on in the world, taken up in glory”–the fact of the incarnation is beyond question. That Jesus is fully man and fully God is clearly taught in Holy Scripture. In, Philippians 2:6-8, Paul says of Jesus, “who, though he was in the form of God, did not count equality with God a thing to be grasped, but made himself nothing, taking the form of a servant, being born in the likeness of men. And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross.” Jesus is God in human flesh, he has two natures (one human, one divine), yet he is one person.
In the Incarnation, God came to earth in the person of Jesus Christ to save us from our sins. That the Word became flesh to save us from our sins is the very heart of Christianity.