4 As it is written in the book of the words of Isaiah the prophet:

“A voice of one calling in the wilderness, ‘Prepare the way for the Lord, make straight paths for him. 5 Every valley shall be filled in, every mountain and hill made low. The crooked roads shall become straight, the rough ways smooth. 6 And all people will see God’s salvation.’”

Isaiah wrote these words seven hundred years before John the Baptist appeared by the Jordan. He wrote them into a particular historical moment — Israel in exile, the nation broken and displaced, the promises of God seemingly suspended by the weight of their own failure. And into that darkness he spoke of a voice. A voice calling in the wilderness. Preparing a way.

Luke reaches back and pulls this passage forward because he wants his readers to understand what they are seeing when John appears. John is not an isolated phenomenon. He is not a new idea. He is the fulfillment of something that was already being spoken about when the world was a very different place. The arrival of John in the wilderness of Judea is the moment a seven-hundred-year-old prophecy steps out of the scroll and into history.

What Isaiah described as coming — Luke is saying — is here.

But notice what Isaiah focuses on. Not the one who is coming. The voice that prepares the way for the one who is coming. The whole passage is about preparation. About what needs to happen before the arrival. About the work that precedes the moment everyone is waiting for.

The voice is not the destination. The voice exists entirely in relation to the one coming after it.

The location matters. A voice calling in the wilderness.

The wilderness in the biblical imagination is not simply a geographic description. It carries a history. Israel wandered in the wilderness for forty years — the long, painful season between Egypt and the Promised Land. The place where God provided manna and water from rock and the pillar of fire. The place where the old generation died and the new one was formed. The place between what was and what was coming.

The wilderness is the place of stripping down. Of being removed from the comfortable structures and distractions that allow people to avoid the deeper questions. In the city there are a thousand things to look at. In the wilderness there is the sky and the sand and the question of what you actually believe about God.

John appears there deliberately. People have to leave the city and go out to him. The going out is itself part of what is being asked. Before they can receive what John is preaching they have to make the journey — have to remove themselves, at least temporarily, from the ordinary world and enter the space where preparation can happen.

The wilderness is where preparation tends to occur. Not in the comfortable places. Not in the well-provisioned ones. In the stripped-down place where what is unnecessary has been removed and what remains is the actual condition of the heart before God.

The imagery Isaiah uses is drawn from the ancient practice of road building before a royal visit.

When a king was coming to a region, workers would be sent ahead to prepare the roads. Valleys filled in. Mountains cut down. Crooked paths straightened. Rough surfaces smoothed. The king was not expected to navigate difficult terrain — the terrain was expected to be made navigable for the king. The preparation of the road was an act of honour toward the one who would travel it. It declared, in the language of engineering and labour, that the one coming was worth the work of preparation.

This is the image Isaiah reaches for when describing what needs to happen before the Lord comes. And the application Luke is drawing is unmistakable — the preparation is not of literal roads. It is of the human heart.

Every valley filled in. Every mountain made low. The crooked roads straightened. The rough ways smoothed.

The valleys are the places of depression and despair — the low places where hope has collapsed and the sense of God’s presence has become remote. They need to be filled in — not with false optimism but with the genuine substance of what God has promised. The mountains are the places of pride and self-sufficiency — the high places where a person has elevated themselves to a position that leaves no room for God to arrive. They need to be brought low. The crooked roads are the patterns of dishonesty and self-deception — the rationalizations and compromises that have bent the path away from what is true. They need to be straightened. The rough ways are the places of hardness — the calloused surfaces that have formed over years of pain or cynicism or disappointment. They need to be smoothed.

The preparation Isaiah is describing — and that John is calling people to — is not a surface adjustment. It is a comprehensive renovation of the interior landscape. Everything that would hinder the arrival needs to be addressed before the arrival comes.

There is a tendency to want the arrival without the preparation. To want the experience of God’s presence without the work of making the interior roads navigable. To want the mountain top without the valley work that precedes it.

But the passage does not allow that short-cut. The voice comes before the arrival. The preparation precedes the coming. The road must be made before the king travels it.

This is not a picture of earning God’s presence through sufficient self-improvement. God does not come only to those who have adequately prepared. The preparation is not what makes God willing to come — it is what makes us capable of receiving what He brings when He does. A heart full of unaddressed pride cannot receive what a humble heart can receive. A life full of crooked patterns cannot hold what a straightened life can hold. The preparation is not for God’s benefit. It is entirely for ours.

John’s preaching at the Jordan was a call to exactly this kind of work. Repentance — the turning of the whole self in a new direction — is the human side of the preparation the passage describes. The valley of despair addressed by honest acknowledgement and renewed trust. The mountain of pride brought low by genuine humility. The crooked path of self-deception straightened by honest reckoning with what is true. The rough surface of a hardened heart smoothed by the willingness to be vulnerable before God again.

None of it is comfortable. All of it is necessary.

The passage ends with a horizon that would have been startling to its original audience.

And all people will see God’s salvation.

Isaiah is writing to Israel. John is preaching to Jews who have come out to the Jordan. And yet the promise at the end of the preparation passage is not for Israel alone — it is for all people. Every nation. Every tongue. Every person who has been waiting, in whatever language and whatever part of the world, for the salvation that is coming.

The road being prepared is not a private road to a private destination. It is being made straight so that what arrives can reach everyone. The valleys being filled in and the mountains being brought low are the removal of obstacles not just for one people but for the whole human family. What God is doing in sending the one whose way John is preparing is not a local project. It is the event toward which all of human history has been moving.

All people will see it. The Jew and the Gentile. The near and the far. The person who has been waiting for centuries inside the covenant promises and the person who has been waiting without knowing what they were waiting for. All of them — when the preparation is complete and the one comes whose sandals John is not worthy to untie — will see the salvation of God.

Luke is writing for a largely Gentile audience and he knows it. The inclusion of this line from Isaiah is not accidental. It is the signal, right at the beginning of John’s appearance, that what is coming is for them too. That the voice in the wilderness is preparing a road wide enough for everyone.

The passage leaves us with a question that is worth sitting with honestly.

What is the condition of the interior road?

Not in the general sense — but specifically. Where are the valleys that have not yet been filled in — the low places of despair or hopelessness or a sense of God’s absence that has settled into something close to permanent? Where are the mountains that need to be brought low — the areas of pride or self-sufficiency where there is genuinely no room for God to arrive because the space is already occupied? Where are the crooked paths — the patterns of rationalisation or self-deception that have bent the way of living away from what is actually true? Where is the surface rough and hardened — calloused by disappointment or hurt or the accumulated weight of unanswered questions?

The voice in the wilderness is still calling. The preparation it announces is still the work that precedes the arrival. And the arrival it prepares the way for is still the one worth doing the work for.

Make the paths straight. Fill in the valleys. Bring the mountains low. The one coming after is worth every bit of the preparation.

All people will see God’s salvation. Let it begin with the road inside.

All glory to God — forever and ever. Amen.

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