The Doctrine of the Incarnation

Joonas Laajanen

For ye know the grace of our Lord Jesus Christ, that, though he was rich, yet for your sakes he became poor, that ye through his poverty might be rich. (2 Corinthians 8:9)

It is that time of the year when many believers around the globe celebrate the incarnation of Christ. On the other hand, it’s also the time when many other people think instead about Santa Claus, prime rib roasts, and getting double pay. Like any other time of the year, the Son of God seems to be, to many, irrelevant, and the deep questions of life are once again avoided. We should of course know that the depravity of man does not take a break for Christmas. If anything, this season magnifies how quickly and strongly the natural man twists and exchanges the true God for idolatry.

As Christians, we can feast and laugh, but not for our vanity’s sake. We are to do all lawful things for the glory of God, with our hearts, souls, and minds. If we say that Christmas is about the Lord Jesus, it must be sincere, visible, and understandable. If not, we take the name of our Lord in vain (Ex. 20:7).

The doctrine of the incarnation and the miraculous birth of our Lord are essential truths for the salvation of men and women. It is not a coincidence that Christmas is the time when congregations make greater efforts to reach out to the lost. For the sake of renewing our minds around the history-changing event of the birth of our Lord, let’s review the indispensable doctrine of the incarnation:

Old Testament: Waiting for the Birth

What is meant by Christ’s “incarnation?” In the Old Testament, God revealed himself as the only true and living God, the eternal one, who is unchangeable in His being, wisdom, power, holiness, goodness, justice, and truth (Deut. 5:6; Mal. 3:6). Numerically God is “mono,” or one. God also revealed that He is not alone in Himself. This is where the mystery (not knowable to man through natural revelation) lies. Yahweh is not simply one person, but three persons: The Lord God (Lev. 11:44), the Angel of the Lord (Ex. 3:2, 6; 24:20–23), and the Spirit of the Lord (Gen. 1:2; 2 Sam. 23:2). No, it was not given to the saints in the Old Testament to extrapolate on this (Judg. 13:18), but when they saw the Son in a theophany, they knew that they had seen God (Gen. 18:1; Judg. 13:22). When the Spirit operated in and through the saints, they knew Him as an indispensable person that they loved, not as a mere force or an energy (2. Sam. 23:2; Ps. 51:11).

Additionally, God revealed through covenant, promise, type, and prophesy, that salvation for mankind would be accomplished by the “seed of the woman.” From the beginning it was clear that the savior would be a man, or as Geerhardus Vos puts it: “God would bring out of the human race victory over the serpent. In that faith could rest.” (Biblical Theology, The Banner of Truth, 44).

The original promise was given in the context of a new covenant after the fall (Gen. 3:15–21) when the foundation of the relationship between God and His people was changed from works to grace. After this many magnificent and mysterious events happened (Noah’s flood, the testing of Abraham, the life of Joseph, the Exodus etc.) so that the promise would come to fulfillment at the appointed time. Already at the time of writing, these events served as types (intentional, prophetic foreshadowings of the future), as they were meant to be interpreted in the light of Gen. 3:15. This becomes most clear when specific, elaborate prophesies were written down about the Messiah. Here the Old Testament doctrine of the Trinity and the expectation of the Messiah are tied together in a ”clear mystery” (the oxymoron is purposeful):

Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel. (Is. 7:14 KJV)

For unto us a child is born, unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counsellor, The mighty God, The everlasting Father, The Prince of Peace. Of the increase of his government and peace there shall be no end, upon the throne of David, and upon his kingdom, to order it, and to establish it with judgment and with justice from henceforth even forever. The zeal of the Lord of hosts will perform this. (Is. 9:6–7 KJV)

The redemption of God’s people and the judgment of her enemies would be through a son, born of a woman. Isaiah was not writing about just another man. He is unique even in his birth – born of a virgin. And we are talking of a person who has more in him than what constitutes a human being. The names given to him testify of his divine nature. He is truly God, the Creator, and the final Judge. He is the one, beside whom “there is no Savior.” Messiah would be truly God and truly a (sinless) man.

The Nativity and the Name ‘Jesus’

From the Old Testament hope of the birth of the divine Messiah, we come to look at the simple and yet profound account in Matthew:

Now the birth of Jesus Christ was on this wise: When as his mother Mary was espoused to Joseph, before they came together, she was found with child of the Holy Ghost.

Then Joseph her husband, being a just man, and not willing to make her a public example, was minded to put her away privily.

But while he thought on these things, behold, the angel of the Lord appeared unto him in a dream, saying, Joseph, thou son of David, fear not to take unto thee Mary thy wife: for that which is conceived in her is of the Holy Ghost.

And she shall bring forth a son, and thou shalt call his name Jesus: for he shall save his people from their sins. (Matt. 1:18–21 KJV)

The work of the Holy Spirit is emphasized in the account. The Spirit of the Lord, already revealed in the Old Testament, is the creator of life. He breathed out the human soul of the Second Adam and preserved him from all corruption. From this we also learn that when a woman has conceived, a new life of a true human being has started.

The mother of Jesus, Mary, is presented as a humble woman, a true believer who was given an immense privilege. Very few would have shown such faith and courage. Yet far is the thought of her being without sin. After all, Joseph could very well at first consider that Mary had lapsed into a terrible sin. I mention this because of the prevalent “Mariolatry” around the world. Modesty is required when we give praise to any of our fellow sinners – even if they were greatly used by God.

The name that was to be given is another important emphasis: Jesus. How beautiful is that name? And how it should vex our souls when we hear that name reviled and lightly used? Listen to the explanation: He shall save his people from their sins. Note the following from these words.

First, Jesus never fails. There are doctrines of men that present to us a Christ that tries His best to save all, but ultimately is dependent on man’s cooperation. But the divine intention behind the name casts these theories aside. The sovereign power and love of Christ are always the first causes and the explanation of any man’s salvation:

He shall see of the travail of his soul, and shall be satisfied (Is. 53:11a)

Secondly, Jesus has a people. These are the members of the Church, the elect, the bride, and the “sheep that hear the Shepherd.” The saving mission of God is therefore particular, not universal. As Isaiah 53 quoted above continues:

by his knowledge shall my righteous servant justify many; for he shall bear their iniquities. Therefore will I divide him a portion with the great, and he shall divide the spoil with the strong; because he hath poured out his soul unto death: and he was numbered with the transgressors; and he bare the sin of many, and made intercession for the transgressors. (Is. 53:11b–12)

Thirdly, salvation is from our sins. Christ was born to remove the eternal consequences of sin. This is truly good news. Jesus is able to wash you clean and forgive every sin you have ever committed. The dirt and the filth of your souls can be brought to light, and yet you can stand before God through Jesus. In a time when the word, “gospel” is typically associated more with social justice than salvation, it is to be remembered, that only as people are saved from the penalty (eternal condemnation), power (a life of sin), and ultimately the presence (desire and tendency to evil) of sin, that the world will witness a lasting change for good.

Protection Against Heresy

Unlike the synoptic gospels, John starts his testimony with a doctrinal statement about the divinity of the Son and about the incarnation. This is extremely valuable since the spirit of antichrist perverts these truths out of shape:

In the beginning was the Word, and the Word was with God, and the Word was God…

And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father), full of grace and truth. (John 1:1, 14 KJV)

Our Lord was before the beginning, and He was with the Father, and He was what the Father was. There never was a time when the Father was without the Son. This is why Christians believe that the Father and the Son are absolutely equal, immutable, and unchanging in their being and attributes. God does not have different departments within himself so that the person of the Father would have a “bit more” of glory or authority than the person of the Son.

Why is this important? Because we cannot afford to meddle with the two natures of Christ or the doctrine of the Trinity when we celebrate the birth of our Savior. Jesus, who saves us from our sins, is truly God and truly man. This means that we are warned to not use one of these realities to take anything away from the other.

In the incarnation, the Son became something he never was before, namely a man. But as He was made flesh, He did not lose or pause what He always was. Jesus’ humility, humiliation, and poverty were in the act of a voluntary incarnation as he welcomed the limited and changing realities of humanity to himself. This He did for the salvation of undeserving sinners:

Who, being in the form of God, thought it not robbery to be equal with God:

But made himself of no reputation, and took upon him the form of a servant, and was made in the likeness of men:

And being found in fashion as a man, he humbled himself, and became obedient unto death, even the death of the cross. (Phil. 2:6–8 KJV)


So what is meant by the incarnation of Christ? Here is a simple answer:

The incarnation is the Son’s true partaking of our flesh and blood (Heb. 2:14), a gift of God to fallen mankind, purposed to lead us into life eternal (John 3:16) that we might praise Jesus Christ, the firstborn among many brethren (Rom. 8:29).

May you have a very merry Christmas as you meditate on the love of Christ for you.

And she brought forth her firstborn son, and wrapped him in swaddling clothes, and laid him in a manger; because there was no room for them in the inn. (Luke 2:7 KJV)

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