Isaiah 40:3–4 (ESV) … A voice cries: “In the wilderness prepare the way of the Lord; make straight in the desert a highway for our God. Every valley shall be lifted up, and every mountain and hill be made low; the uneven ground shall become level, and the rough places a plain.”
Isaiah hears a voice! What is God saying? Three things.
One: The King is coming. He comes to us as we are, where we are, in the wilderness and desert of our real lives. He wants us to get ready to receive him, because right now we aren’t ready. We know from Luke 3:1–18 that Jesus is the coming King and that the readiness we need is newness of life. We can’t hide behind denominational labels, however correct (“We have Abraham as our father,” Luke 3:8). What we need is new selves. Prepare the way of the Lord!
Two: God will accomplish his purpose. Every valley shall be lifted up, and so forth. Isaiah is not talking about literal, topographical change. He is talking about the upheaval of true repentance. He is talking about a new moral topography, a new social landscape. He is talking about the disruptive advance of salvation. He is saying that lifting and lowering and leveling and smoothing are necessary to the kingdom of Christ. He is talking about depression being relieved, pride being flattened, troubled personalities becoming placid, and difficult people becoming easy to get along with. And he is also implying that if we cling to the status quo and refuse God’s upsetting but constructive salvation, we risk having no part with Christ.
Three: The glory of the Lord Jesus will be revealed to the whole world. We can be certain of it. God has decreed it: “… for the mouth of the Lord has spoken.” His glory will be admired and delighted in and trembled at everywhere. The great sin of our race is to diminish God, but he has resolved to overcome all God-trivializing obstacles and magnify himself in our eyes through Jesus Christ the Lord.