Christmas is the most surprising and unexpected love story ever told. God doesn’t arrive on earth as a conquering king or powerful ruler, but as a vulnerable baby boy, laid in an animal’s feeding trough. Born to an ordinary young woman in an insignificant town, the Creator of the universe shows up in the most unlikely way imaginable, in the most unlikely place, to the most unlikely people. And because of his great love, God sends his only Son to become one of us and redeem us.

It’s so unexpected that over the years, of course, many people have been sceptical about it. For a first-century Jew, the notion of God becoming human would have been utterly unthinkable. They expected a Messiah to come, certainly, but they didn’t know that the Author of human history would write himself into the story. The mystery and surprising nature of the incarnation has led some to dismiss it as just a “nice fairy tale”—suitable for a school nativity, perhaps, but not rooted in history.

Yet as the Christian writer J.I. Packer describes it:
“The Almighty appeared on earth as a helpless human baby, needing to be fed and changed and taught to talk like any other child. The more you think about it, the more staggering it gets. Nothing in fiction is so fantastic as this truth of the Incarnation.”

As Christians, we should embrace the wonderful mystery of the incarnation whilst also recognising that God becoming man was a rational decision. In fact, it was necessary for us. It’s surprising, but it makes sense, and it offers the most wonderful hope to you and me.

So why did God the Son become a human being?

1. To Show Us What God Is Like

When the apostle John reflects on his time with Jesus, he writes: “The Word became flesh and made his dwelling amongst us. We have seen his glory, the glory of the one and only Son, who came from the Father, full of grace and truth.” As Charles Wesley puts it so beautifully in his carol: “Veiled in flesh, the Godhead see, Hail, the incarnate deity.”

They say you only really get to know someone when you live with them. When you share a flat with a flatmate or get married, you quickly discover another person’s habits, quirks, likes and dislikes. Of course, when you live with someone, it doesn’t take long before you also discover their flaws and sins—the irritating habits, the sharp words, the selfishness that emerges under pressure.

Here’s the difference with Jesus. When he stepped into our world, those who lived with him didn’t see any flaws or sin at all. The more time they spent with him, the more clearly they saw the glory of God himself. Throughout the Old Testament, God’s presence was with his people in powerful but often mysterious ways—in the temple, in the pillar of fire by night and cloud by day. God was present, but he remained, in many ways, veiled.

But now, in the incarnation, we see the pinnacle of God’s presence with his people. It’s no longer mediated through structures or symbols—it’s personal. As one translation puts it, the Word “moved into the neighbourhood.” This is remarkable because, as Paul writes in 1 Timothy, God is the one “who alone is immortal and who lives in unapproachable light, whom no one has seen or can see.” In Exodus, when Moses asked to see God’s glory, God told him, “You cannot see my face, for no one may see me and live.” God’s majesty and holiness make him utterly inaccessible to sinful human beings.

And yet—here is the wonder of Christmas—this very same God chose to make himself visible and known. Isn’t that such a profound kindness to us? We can’t stand in the presence of the living God without dying, and so God condescends to us, to show us his glory and reveal his love.

Think of cross-cultural missionaries who spend years learning a new language just so they can speak in the heart language of the people they’re trying to reach. The incarnation is the ultimate cross-cultural mission, as God the Son leaves the infinite splendour and majesty of heaven to take on fragile human flesh, born to an obscure couple in a small town, all so that we can finally know what God is truly like.

For those who are spiritual seekers, this is extraordinarily good news. According to recent surveys, over two-thirds of people in the UK still believe in “a God or higher power,” but increasingly, many say, “I don’t know who or what that is.” For the Christian, there is no unknown God. He has made himself known by becoming one of us. If you want to know God better, start with Jesus. As Don Carson says: “Do you want to know what the character of God is like? Study Jesus. Do you want to know what the holiness of God is like? Study Jesus. Do you want to know what the glory of God is like? Study Jesus all the way to that wretched cross.”

2. To Save Us

In Matthew’s Gospel, an angel appears to Joseph in a dream with specific instructions: “You are to give him the name Jesus, because he will save his people from their sins.” Jesus’ very name means “God saves,” and the message that God saves sinners from the big, inescapable problem of sin and death is bullseye at the centre of the Christmas story. As Charles Wesley writes: “Mild he lays his glory by, Born that man no more may die, Born to raise us from the earth, Born to give us second birth.”

The writer of Hebrews explains that “since the children have flesh and blood, he too shared in their humanity so that by his death he might break the power of him who holds the power of death.” This rescue is powerful because it’s complete. When it says Jesus “shared in their humanity,” it doesn’t mean in the sense of a bring-and-share picnic where you have a little bit of this and that. He participated as a full member of the human race. As the verse continues, he was “made like them, fully human in every way.”

Back in the fourth century, Gregory of Nazianzus rightly insisted that Jesus shared fully in our humanity, capturing it with this statement: “That which he has not assumed he has not healed; but that which is united to his Godhead is also saved.” Like a conscientious firefighter who searches every room in a house before announcing the all-clear, Jesus assumed every part of human existence—mind, body and soul—so that we would find full healing from our sin-sickness.

A human problem requires a human solution. When Adam and Eve sinned, the curse came through a human representative. Justice demands that restoration must also come through a human representative. The Old Testament sacrificial system used animals, but these were merely shadows. We needed a faithful high priest who was himself human yet without sin.

If you and I are both drowning in debt, there’s no point in me asking you for help—you’ve got your own debts to worry about. Every person who has ever lived (except Jesus) has had their own debt of sin. We’re all spiritually bankrupt. But Jesus came as the second Adam, faithful and perfectly obedient. He faced temptation throughout his entire life and never sinned, which is how he’s able to free those held in slavery to sin.

This is why Jesus didn’t just appear as a thirty-something adult ready to go to the cross. He was born as a baby and experienced every stage of human development, not only dying for us but living the life we should have lived, obeying God where Adam failed. As Paul says in Romans: “By the one man’s obedience the many will be made righteous.”

For believers, this means your acceptance before God isn’t based on your performance this week—it’s based on Jesus’ perfect performance in your place. We can enjoy our salvation, knowing it’s complete.

3. To Sympathise With Us

The singer-songwriter Joan Osborne released a song in the 1990s that asked, “What if God was one of us? Just a stranger on the bus, trying to make his way home?”

Implicit in these lyrics is the thought: if only God were one of us, then he’d be able to understand what we go through.

The remarkable news of the incarnation is that God is one of us. Hebrews tells us: “Because he himself suffered when he was tempted, he is able to help those who are being tempted.” And again: “We do not have a high priest who is unable to sympathise with our weaknesses.”

Some people think Jesus’s temptations must have been easier because he was God, but that’s not right. While Jesus didn’t have a sinful nature, he faced external temptations far more intense than anything we’ll experience. Satan threw everything at Jesus in direct, focused, relentless attacks. And because Jesus never sinned, he fought every temptation all the way to the end.

Think about a marathon (this will be easier for those of us who have done one). Every mile tests your endurance, focus, and willpower – and the moment you quit, the pressure is off. The same is true of temptation. When you give in to that angry outburst or indulge in gossip, there’s a temporary sense of relief. But Jesus ran the marathon of temptation his entire life and ran it faithfully. As C.S. Lewis puts it: “Bad people, in one sense, know very little about badness. They have lived a sheltered life by always giving in. Christ, because he was the only man who never yielded to temptation, is also the only man who knows to the full what temptation means.”

This means when we come to Jesus with our struggles, he doesn’t respond with “Just get over it.” He understands because he’s been there. You can come to Jesus with anything—not your ‘Sunday-best’ self, but your weaknesses, failures, temptations and struggles—knowing that he truly sympathises with you from personal experience. When you’re weary of swimming against the cultural tide, when you’re tired of being mocked for your beliefs, Jesus actually sympathises with you. He’s merciful and faithful to help you through the power of the Holy Spirit.

---

So why did God become man? To show us what God is truly like—full of grace and truth, approachable and compassionate. To save us completely—not just dying for our sins but living the perfect life on our behalf, entering fully into our humanity so that every part of us could be redeemed. Salvation is not achieved by our ascent to God, but by God’s descent to us. To sympathise with us—becoming our merciful and faithful high priest who truly understands our struggles and now helps us in our weakness. This is why Christmas is not only astonishing in its claims, but also compelling in its coherence. It remains the greatest love story ever told. As the carol proclaims: “Hark! the herald angels sing, Glory to the newborn King: Peace on earth, and mercy mild, God and sinners reconciled!”