The Heart of It All: The Incarnation (Part 1)

June 28, 2011

by Peter Amsterdam

Audio length: 21:53

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(For an introduction and explanation regarding this series overall, please see The Heart of It All: Introduction.)

In the articles titled “The God-Man” and “The Trinity” we explored the biblical truth of Jesus’ deity—that He is truly God. In “The Incarnation” articles we will delve into the biblical explanation of Jesus’ humanity—that He was fully man as well as fully God.

The humanity of Jesus

According to God’s plan of salvation, Jesus’ humanity is as important as His deity, because our salvation depends on Jesus being both fully God and fully man.

Because He is one of the persons of the Trinity—God the Son—salvation is possible. Only one who is God can bear the weight of the sins of the world. Only one who is eternally God can bring a sacrifice of infinite value and render perfect obedience to the law of God, bear the wrath of God redemptively, and so free others from the judgment of the law.[1]

By the same token, only one who shares in humanity can make salvation possible. Because the first man, Adam, sinned and brought condemnation to all men, it was necessary that another human bear the punishment and receive God’s judgment upon himself—for only a human being can vicariously represent mankind.

In fact Christ has been raised from the dead, the firstfruits of those who have fallen asleep. For as by a man came death, by a man has come also the resurrection of the dead. For as in Adam all die, so also in Christ shall all be made alive.[2]

It was therefore necessary for Jesus, who is the second person of the Trinity, to become incarnate, to take on full humanity, to be both fully God and fully man, to make salvation possible.

While the apostles and early Christians understood that Jesus was God as well as human, the actual doctrine of the Incarnation came later. The word incarnation is a technical word in Christian theology that comes from the Latin word carnem, meaning flesh. The Incarnation means that Jesus is God in human flesh. Jesus’ incarnation was the only time in history when God became human—God incarnate, God in flesh.[3] Chronologically, the Incarnation was formally expressed as a doctrine after the doctrine of the Trinity was developed. The Trinity explained who God is and the Incarnation expresses that Jesus is both God and human. As with articulating the doctrine of the Trinity, it took some time, and some controversy, to hammer out the concept and the wording to express that Jesus was fully God and fully man.

Often people focus on the deity of Jesus and push His humanity into the background. But while Jesus was God living on earth in human flesh, He was just as human as you and me. He had the same physical needs and weaknesses that we have. He had the same physical and mental limitations. He had the same emotions. He was tempted to sin and had internal spiritual suffering, just as we do. He was a man, and He was born, lived, and died just like any man. He had human nature, meaning both a material body and a rational soul, or mind.

Let’s take a look at the verses that show Jesus’ humanity. I’ll list them by category.

Human elements—material body and rational soul

Jesus had both of the major elements of human nature—a material body and a rational soul. He spoke of His body and of His soul/spirit (in some instances soul and spirit are used interchangeably to mean the same thing). He spoke of His flesh and bones. The book of Hebrews speaks of His having flesh and blood. In other verses He spoke of having a soul or spirit.

“See My hands and My feet, that it is I Myself. Touch Me, and see. For a spirit does not have flesh and bones as you see that I have.”[4]

Since therefore the children share in flesh and blood, He Himself likewise partook of the same things.[5]

Then He said to them, “My soul is very sorrowful, even to death; remain here, and watch with Me.”[6]

Then Jesus, calling out with a loud voice, said, “Father, into Your hands I commit My spirit!”[7]

These verses show that Jesus had the necessary elements for being human.

Jesus called Himself a man and others attested to His being a man:

You seek to kill Me, a man who has told you the truth that I heard from God.[8]

“Men of Israel, hear these words: Jesus of Nazareth, a man attested to you by God with mighty works and wonders and signs that God did through Him in your midst…”[9]

For as by a man came death, by a man has come also the resurrection of the dead.[10]

As with all humans, Jesus was ruled by the natural laws of human growth and development. He was born, He grew physically from childhood to manhood. He went through the normal learning process a child does. He grew in knowledge, understanding, wisdom, and responsibility like any other human does as he grows older. He grew strong in spirit over time, most likely by learning lessons, such as obedience to His parents, through suffering, and other experiences. While there is no scriptural mention of His being sick, it can be assumed that He may have been ill from time to time.

She gave birth to her firstborn son.[11]

The child grew and became strong, filled with wisdom. And the favor of God was upon Him.[12]

Jesus increased in wisdom and in stature and in favor with God and man.[13]

Although He was a son, He learned obedience through what He suffered.[14]

Human needs, weaknesses, and emotions

Jesus had the physical weaknesses and needs that we have as humans. He got hungry, thirsty, tired. He became physically weak. He became weary. Once He was so tired that He slept soundly in a fishing boat in the midst of a violent storm.

And after fasting forty days and forty nights, He was hungry.[15]

Jesus, wearied as He was from His journey, was sitting beside the well. It was about the sixth hour. A woman from Samaria came to draw water. Jesus said to her, “Give Me a drink.”[16]

There arose a great storm on the sea, so that the boat was being swamped by the waves; but He was asleep.[17]

As they led Him away, they seized one Simon of Cyrene, who was coming in from the country, and laid on him the cross, to carry it behind Jesus.[18](It is presumed that Jesus was too weak, due to the torturous whipping, to carry the cross Himself.)

Jesus experienced emotions as we do. He felt compassion for people. He pitied those in need. He wept. He marveled, was deeply moved, got angry. He grieved. He prayed in desperation, was sorrowful, was in psychological agony. He was sometimes troubled (from the Greek word tarrasso, meaning anxious or suddenly surprised by danger). He had friends and He loved them.

When He saw the crowds, He had compassion for them, because they were harassed and helpless, like sheep without a shepherd.[19]

When Jesus heard this, He marveled and said to those who followed Him, “Truly, I tell you, with no one in Israel have I found such faith.”[20]

When Jesus saw her weeping, and the Jews who had come with her also weeping, He was deeply moved in His spirit and greatly troubled.[21]

Jesus wept.[22]

He looked around at them with anger, grieved at their hardness of heart, and said to the man, “Stretch out your hand.” He stretched it out, and his hand was restored.[23]

Being in an agony He prayed more earnestly; and His sweat became like great drops of blood falling down to the ground.[24]

Then He said to them, “My soul is very sorrowful, even to death; remain here, and watch with Me.”[25]

After saying these things, Jesus was troubled in His spirit, and testified, “Truly, truly, I say to you, one of you will betray Me.”[26]

“Now is My soul troubled. And what shall I say? ‘Father, save Me from this hour’? But for this purpose I have come to this hour.”[27]

Now Jesus loved Martha and her sister and Lazarus.[28]

Like every human being, Jesus died. His body ceased to have life.

When Jesus had received the sour wine, He said, “It is finished,” and He bowed His head and gave up His spirit.[29]

Then Jesus, calling out with a loud voice, said, “Father, into Your hands I commit My spirit!” And having said this He breathed His last.[30]

The people whom Jesus grew up with and lived among until the start of His public ministry all seemed to consider Him a normal human, which is seen by their reaction to Him once He began His ministry. After He had been doing miracles and preaching in Galilee and large crowds followed Him, He visited His hometown of Nazareth and was rejected by His former neighbors and townspeople.

And when Jesus had finished these parables, He went away from there, and coming to His hometown He taught them in their synagogue, so that they were astonished, and said, “Where did this man get this wisdom and these mighty works? Is not this the carpenter’s son? Is not His mother called Mary? And are not His brothers James and Joseph and Simon and Judas? And are not all His sisters with us? Where then did this man get all these things?” And they took offense at Him. But Jesus said to them, “A prophet is not without honor except in his hometown and in his own household.” And He did not do many mighty works there, because of their unbelief.[31]

Even His brothers didn’t believe in Him, though some of them eventually became known as believers and church leaders—James and Jude, and perhaps His other brothers as well.

For not even His brothers believed in Him.[32]

If those who lived with and around Him for most of His life wondered where He got the wisdom and knowledge to speak and preach so authoritatively, and were astonished, then it’s fairly clear that they looked at Him as a normal person; not God, not even a great teacher, but just a normal human being.

Martin Luther expressed the reality of Jesus’ full humanity when he said: He ate, drank, slept and waked; was weary, sad, joyous; wept, laughed; was hungry, thirsty, cold; sweated, talked, worked, prayed.[33]

All of the preceding verses show that Jesus was fully human. He was the same as you or me in regard to our humanity and human nature. He experienced life as we do, with the same physical and mental strengths and weaknesses. He was human in every sense except sin. That’s the one difference. Jesus didn’t sin, ever.

Jesus did not sin, but was tempted

The following verses speak of Jesus’ sinlessness.

God made Him who had no sin to be sin for us, so that in Him we might become the righteousness of God.[34]

He committed no sin, neither was deceit found in His mouth.[35]

You know that He appeared to take away sins, and in Him there is no sin.[36]

Which one of you convicts Me of sin?[37]

Because Jesus didn’t sin, it wasn’t necessary for Him to die for His own sins, but He could instead die for the sins of mankind.

You may wonder if Jesus could sin. The answer based on Scripture seems to be no, He couldn’t. If you look at Scripture, it tells us the following:

1) Jesus didn’t sin, as shown in the verses above.

2) Jesus was tempted in every respect that we are, and as such we know He was truly tempted to sin.

For we do not have a high priest who is unable to sympathize with our weaknesses, but one who in every respect has been tempted as we are, yet without sin.[38]

3) Jesus is God, and God cannot be tempted with evil.

Let no one say when he is tempted, “I am being tempted by God,” for God cannot be tempted with evil, and He Himself tempts no one.[39]

One of the attributes of God is His holiness, which means He is separated from sin. God can’t sin; if He did, He would not be God.

The Scriptures tell us that Jesus was fully God and was fully man. It also tells us that Jesus was tempted and that God can’t be tempted.

If Jesus’ human nature existed independently from His divine nature, then He would have been similar to Adam and Eve when they were first created, in that He would have been free of sin but theoretically able to sin. But Jesus’ human nature never existed apart from His divine nature, as both natures existed in one Person. An act of sin would have been a moral act, which seems as if it would have involved the whole person of Christ, both His divine and human natures. If that had happened, then the divine nature of Jesus would have sinned, meaning God had sinned, and that means He would not be God. But that’s not possible, because it would mean God going against His own nature, something that God doesn’t do. As such, it can be seen that the union of Jesus’ human and divine natures in one person prevented Him from being able to sin. However, exactly how that happened we can’t know. It’s one of those mysteries that we face in Christianity, which is understandable considering that Jesus is the only one who has ever had two natures—the nature of God and the nature of man—so it’s not unreasonable that it’s difficult, if not impossible, for us to know how such things worked within Him.

I want to add that every theologian whose works I have read concurs on this point, that Jesus could not have sinned; at the same time, each agrees that the temptation to sin was just as real to Jesus as it is to us, for He was human and tempted in all things as we are, with the same intensity of temptation. While we don’t fully understand how it can work to be tempted yet be unable to sin, we know from Scripture that Jesus was genuinely tempted and yet never yielded to the temptation to sin.

All of us are tempted to sin, which can bring about a deep internal struggle not to. Imagine yourself in a situation where you are in dire straits financially—bills are due, you don’t have the funds to pay them, and you may lose your house over it. It could mean being homeless, and if not that, you’ll at least have to move, which will affect the school your children can go to, and thus their education. As it is, you are having a hard time putting decent food on the table. Along comes an opportunity for you to make a large amount of money, which will take care of your present and future financial needs. However, the opportunity requires that you sin through deception. Most of us can probably imagine the struggle of weighing up the benefits of taking the opportunity against the difficulty of making the right moral and ethical choice, and facing the possible consequences of doing so. Still in that scenario, imagine that you decide not to take the “opportunity” and do not sin.

Even though you chose not to sin, and so in this instance were “sinless,” the temptation was still real. It was intense and required an immense amount of faith, grace, and spiritual fortitude to resist. This example may give you some understanding of Jesus’ experience in temptation.

He was fully tempted in all things just as we are, yet in every instance He resisted the temptation and therefore didn’t sin. He had to fight through every temptation in order to resist sin. The appeal to sin that He experienced is the exact same appeal that we experience. The difference is that Jesus didn’t ever yield to temptation, so He didn’t sin.

Christian philosopher and apologist William Lane Craig put it this way:

“So how are we to understand the temptation of Christ? Well, very simply, you don't have to be able to do something in order to be tempted to do it. … Suppose you're in a mad scientist's lab and you really believe that he has a time-traveling DeLorean. He leaves you to guard the lab with strict instructions, ‘Do not take the DeLorean out on a spin through time!’ Now you might be sorely tempted to take a journey through time during his absence—after all, you could come back as soon as you left so that no one would be the wiser! You might have to really struggle to resist that temptation. Little did you know that the scientist was a quack and there was no possibility of your taking a jaunt through time! But you did your duty; you resisted temptation and might even deserve to be commended for it, and might have been strengthened in your moral life by this exercise of your will.

“Or to take a more realistic example, suppose you’re dieting and are tempted to go to the fridge to get the chocolate cake that your wife left there last night. You courageously resist, never knowing that she had already eaten the cake during a midnight raid and the refrigerator was empty! Examples like these show very convincingly, I think, that in order to be tempted to do something, we needn’t be actually able to do the thing we’re tempted to do.”[40]

The fact that an army cannot be defeated in battle doesn’t make the battle any less intense. The soldiers still have to fight and suffer in order to win. That Jesus couldn’t sin doesn’t mean the battle over the temptation to sin was not intense. He still had to fight against it.

He obeyed His Father in all things and thus didn’t sin, but it didn’t come easy. The Bible says that “He learned obedience from the things which He suffered,” and the verse before that speaks of His praying with loud cries and tears.

In the days of His flesh, Jesus offered up prayers and supplications, with loud cries and tears, to Him who was able to save Him from death, and He was heard because of His reverence. Although He was a son, He learned obedience through what He suffered. And being made perfect, He became the source of eternal salvation to all who obey Him.[41]

In the garden of Gethsemane, shortly before being arrested and only hours away from being torturously whipped and then crucified, when praying to His Father, He was obviously struggling with the decision to do His Father’s will, fighting the temptation to not “drink the cup.” He prayed in agony.

Jesus was sorely tempted. He learned obedience. He prayed desperately to do His Father’s will. He didn’t rely on His divine nature to make it easier for Him to obey; instead, He had to fight in His human nature as He faced and overcame all temptations.

When we consider that God the Son chose to humble Himself by taking on human nature, human flesh, and all that being human entails so that each of us would have the opportunity to be forgiven for our sins and live forever, it can’t help but make us love and thank Him for doing so. He laid down His life for us—His physical life as a human, but also in a way His heavenly life as well, as He had to leave it to spend those years on earth as a man. If a comparison could be made, it would be like a human agreeing to being born an earthworm and living as a worm for a certain number of years. What a humiliation that would be, how difficult to know that you were human, but you lived a worm’s life. It’s a thought that might give a fresh outlook on His love for us.

Hereby perceive we the love of God, because He laid down His life for us:[42]

In this the love of God was made manifest among us, that God sent His only Son into the world, so that we might live through Him.[43]

Jesus was without sin. He was holy in all His thoughts and actions, in His feelings, always acting in perfect love toward God and man. He always sought to do the will of His Father, and He succeeded. How He was able to do this is a mystery of faith, but we know from Scripture that it is so.

We have seen in earlier articles that Jesus is fully God, and here that He is fully man. In the next article we will explore the difficulties that the church fathers had in determining how deity and humanity could unite in one person.


Unless otherwise indicated, all scriptures are from the Holy Bible, English Standard Version, copyright © 2001 by Crossway Bibles, a division of Good News Publishers. Used by permission. All rights reserved. Other versions frequently cited are The New International Version (NIV), the New American Standard Bible (NASB), The New King James Version (NKJV), and the King James Version (KJV).


Barth, Karl. The Doctrine of the Word of God, Vol.1 Part 2. Peabody: Hendrickson Publishers, 2010.

Berkhof, Louis. Systematic Theology. Grand Rapids: Wm. B. Eerdmans Publishing Company, 1996.

Cary, Phillip. The History of Christian Theology, Lecture Series. Lectures 11, 12. Chantilly: The Teaching Company, 2008.

Craig, William Lane. The Doctrine of Christ, Defenders Series Lecture.

Garrett, Jr., James Leo. Systematic Theology, Biblical, Historical, and Evangelical, Vol. 1. N. Richland Hills: BIBAL Press, 2000.

Grudem, Wayne. Systematic Theology, An Introduction to Biblical Doctrine. Grand Rapids: InterVarsity Press 2000.

Kreeft, Peter, and Ronald K. Tacelli. Handbook of Christian Apologetics. Downers Grove: InterVarsity Press, 1994.

Lewis, Gordon R., and Bruce A. Demarest. Integrative Theology. Grand Rapids: Zondervan, 1996.

Milne, Bruce. Know the Truth, A Handbook of Christian Belief. Downers Grove: InterVarsity Press 2009.

Mueller, John Theodore. Christian Dogmatics, A Handbook of Doctrinal Theology for Pastors, Teachers, and Laymen. St. Louis: Concordia Publishing House 1934.

Ott, Ludwig. Fundamentals of Catholic Dogma. Rockford: Tan Books and Publishers, Inc., 1960.

Stott, John. Basic Christianity. Downers Grove: InterVarsity Press, 1971.

Williams, J. Rodman. Renewal Theology, Systematic Theology from a Charismatic Perspective. Grand Rapids: Zondervan 1996.

[1] Louis Berkhof, Systematic Theology (Grand Rapids: Wm. B. Eerdmans Publishing Company, 1996), 319.

[2] 1 Corinthians 15:20–22.

[3] Phillip Cary, The History of Christian Theology, Lecture Series, Lecture 11. (Chantilly: The Teaching Company, 2008).

[4] Luke 24:39.

[5] Hebrews 2:14.

[6] Matthew 26:38.

[7] Luke 23:46.

[8] John 8:40.

[9] Acts 2:22.

[10] 1 Corinthians 15:21.

[11] Luke 2:7.

[12] Luke 2:40.

[13] Luke 2:52.

[14] Hebrews 5:8.

[15] Matthew 4:2.

[16] John 4:6–7.

[17] Matthew 8:24.

[18] Luke 23:26.

[19] Matthew 9:36.

[20] Matthew 8:10.

[21] John 11:33.

[22] John 11:35.

[23] Mark 3:5.

[24] Luke 22:44.

[25] Matthew 26:38.

[26] John 13:21.

[27] John 12:27.

[28] John 11:5.

[29] John 19:30.

[30] Luke 23:46.

[31] Matthew 13:53–58.

[32] John 7:5.

[33] James Leo Garrett, Jr., Systematic Theology, Biblical, Historical, and Evangelical, Vol. 1 (N. Richland Hills: BIBAL Press, 2000), 612.

[34] 2 Corinthians 5:21 NIV.

[35]1 Peter 2:22.

[36]1 John 3:5.

[37] John 8:46.

[38] Hebrews 4:15.

[39]James 1:13.

[41] Hebrews 5:7–9.

[42] 1 John 3:16 KJV.

[43] 1 John 4:9.