Thoughts on Luke 3
Two major features of this passage stand out. First is the emphasis on repentance and forgiveness of sins that relates to the preparation needed for the Coming One. There are examples given later in the passage of what that repentance should entail in concrete ways, and the proper response will be fleshed out later in the book. But here, repentance, turning around, walking toward God becomes part of the preparation for His coming. This implies a change of attitude, an openness to the new work of God in the world. Perhaps that is as much an issue of developing a proper sense of expectation, and the trust that goes with it, as it is abandoning sinful actions. Here "repent" and "prepare" are really two parts of the same thing.
For people today this can become a call to live life in expectation, with a view to the reality of God’s Coming to the world. This probably should not take the form of scare tactics about the end of the world or hell. But it should be a call to commitment to live with an attitude of humility, expectation, and repentance, knowing that all of life is shaped by the One who came and is coming.
A second feature is the radical newness that is unfolding here. The metaphor of the "Highway" in Isaiah picks up the idea of a new act of God. That is a major theme of the section of Isaiah from which the quotation here comes (42:8-10,43:18-19, etc; cf. 35:8) as the prophet speaks of the return from Exile. In that sense, the First Advent was one of those acts of God that, metaphorically, could be described quite well as a new "highway" of God's grace, a new historical self-revelation of God.
This becomes an opportunity to simply celebrate the magnitude of this new initiative of God in calling humanity to Himself. When we reflect on how all of this worked out, on the "mountains" Jesus had to remove in the minds and hearts of people, of the "valleys" he had to fill in to reach those who had eyes but could not see, who had ears but could not hear, and when we realize the terrible cost that unfolded from this marvelous act of newness, we are compelled to thankfulness and rejoicing at the wonder of God and His commitment to humanity!
Being careful not to move to allegory, the implication for people’s lives should should be clear: There is a newness with God in which He will remove the obstacles to proper relationship. He will not allow barriers to block His revelation to "all flesh." No matter how sinful, the call still comes, "Turn around!" But the most wonderful part is that the highway back home has already been built.