Charles Spurgeon Commentary Isaiah 40:3-4

"The voice of one that crieth, Prepare ye in the wilderness the way of Jehovah; make level in the desert a highway for our God. Every valley shall be exalted, and every mountain and hill shall be made low; and the uneven shall be made level, and the rough places a plain:" — Isaiah 40:3-4 (ASV)

The voice of him that crieth in the wilderness, Prepare ye the way of the LORD, make straight in the desert a highway for our God. Every valley shall be exalted, and every mountain and hill shall be made low: and the crooked shall be made straight, and the rough places plain:

When God intends to come to people, nothing can stop him or block his road. He will level mountains and fill up valleys, but he will come to his people, somehow or other. And when he comes to them, if he finds many crooked things about them, he will make the crooked straight, and the rough places he will make plain.