Thomas Watson on Why God Became Man


Why did God become man?  It’s a remarkable thing, isn’t it?  And there is no more opportune time throughout the year than now to share with others the reasons for it.

In the Gospel of Luke, we read:

“Unto you is born this day in the city of David a Savior, who is Christ the Lord. And this will be a sign for you: you will find a baby wrapped in swaddling cloths and lying in a manger” (Luke 2:11-12).

These well known words are the heavenly announcement of the Incarnation of the Son of God.  Here in Luke 2, the angel is announcing the birth of Israel’s Savior-King.  However, the announcement is quite unexpected; not that the baby will become a great and powerful leader; but that the great and powerful leader of the Jewish people had become a baby.  Christ, the Lord, had been born.  God had become a human being.

This, according to the angels there in Luke 2, was and is cause for great celebration!  In response to this announcement, heaven explodes into loud rejoicing.

“Glory to God in the highest, and on earth peace among those with whom he is pleased!”  (Luke 2:14)

The Incarnation of Christ is one of the critical doctrines of biblical Christianity.  Without it, the Bible tells us there is no hope for salvation from sin, death, and the righteous judgment of God.  But why is God becoming flesh so critical to our salvation?

I appreciate two of the reasons emphasized by the Puritan preacher Thomas Watson in his classic book A Body of Divinity, in a section on the Incarnation of Christ (“Christ’s Humiliation in His Incarnation”). Though Watson doesn’t use these words himself, the two reasons he emphasizes can be summarized with the words propitiation and imputation.

Propitiation:  Christ became man in order to make propitiation for our sins. 

In other words, the Son of God became man in order to satisfy the wrath of God toward us for our sins.  Christ had to take our sins and the wrath of God toward us for those sins on Himself at the Cross, so that we would not be judged for those sins eternally in hell.  He came as a man to die as a man.  And he died as a man to make God propitious toward sinners who trust in him as Lord.

This is exactly what the writer of Hebrews says in Hebrews 2:17.  “Therefore he had to be made like his brothers in every respect, so that he might become a merciful and faithful high priest in the service of God, to make propitiation for the sins of the people.”

Watson summarizes it this way:

Was there no other way to restore fallen man but that God should take flesh?…God saw it to be the best way for our redemption, that Christ should be incarnate. It was not fit for any to satisfy God’s justice but man; none could do it but God; therefore Christ, being both God and man, is the fittest to undertake this work of redemption…”

And later,  

“Christ took our flesh that He might take our sins upon Him, and so appease God’s wrath. The weight of the whole world’s sins was upon Him” (Watson, A Body of Divinity, pp. 192,194).

Imputation:  Christ became man in order to that his righteousness might be imputed to us through faith.

That is, Christ came to earth as a man to obey His Father perfectly as a man, so that the Father could treat we who trust in Christ as fully obedient people.  Christ’s obedience is credited to those who trust in Him, so that God may treat us not only as if we have never sinned, but as if we have always obeyed.

The Apostle Paul unpacks this idea in various ways.  He puts in this way in Romans 5:18:  “Therefore, as one trespass led to condemnation for all men, so one act of righteousness leads to justification and life for all men.”

And again in 2 Corinthians 5:21:  “For our sake he made him to be sin who knew no sin, so that in him we might become the righteousness of God.”

I really love how Watson explains this awesome truth.  He writes,

“Christ took our flesh that He might make the human nature appear lovely to God…When we fell from God, our nature became repulsive to him; no vermin is as detestable to us as human nature was to God.  It was so vile to God that He could not endure to look upon us.  Christ, taking our flesh, makes this human nature appear lovely to God.  As when the sun shines on the glass it casts a bright luster, so Christ, being clad with our flesh, makes the human nature shine and appear amiable in God’s eyes.” (A Body of Divinity, p. 194).

Later on in this section on Christ’s Incarnation, Watson summarizes the reason the Son of God came to earth as a man with these powerful words:

[Christ came] “that he might take our flesh, and redeem us; that he might instate us into a kingdom. He was poor, that he might make us rich. He was born of a virgin, that we might be born of God. He took our flesh, that he might give us his Spirit. He lay in the manger that we might lie in paradise. He came down from heaven, that he might bring us to heaven.” (A Body of Divinity, p. 196)

It’s no wonder why the angels were so excited to announce the truth of God becoming man. What a wonderful truth this is! Let’s proclaim it joyfully throughout this season. Glory to God in the highest!