Isa 40:4  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 smooth.

In the previous verse we see that the prophet, not just this prophet, but the role of the prophet is to be the voice of one crying in the wilderness. The wilderness is a world without God. A world that has rejected God and the highway that makes its way through the wilderness is established by God through His prophets and by the Blood of Christ Himself. This highway is the Holy Highway of the saints. John the Baptist would famously repeat the words of the prophet Isaiah in John 1:23. John was in the wilderness crying out the message of repentance, He was making the way for His Lord to come in this sense. We too saints are ones crying in the wilderness. We too are a light that dwells in the darkness who cry out to a world lost in sin to repent for the Lord is coming.

Those who walk along the valley floor, along the Highway of Holiness that runs through the wilderness of sin and death and rejection of God, shall be exalted up into the high places of our God where He dwells with the broken and the contrite. For thus says the Lord, I dwell in the high and holy place, with him also that is of a contrite and humble spirit, to revive the spirit of the humble, and to revive the heart of the contrite ones( Isa 57:15) Every mountain and hill or any high thing that exalts itself against the Lord our God shall be brought low. The proud shall indeed be humbled as the glory of the Lord is revealed. The crooked places, the lies, the deceit the vain imaginations of men and all arguments that exalt itself above the Lord shall be made straight as the signs of His coming begin to appear.

All flesh is grass and its beauty is like the the flowers of the field. The world and all who dwell in it fade away. Only by the very breath of God are all things maintained. The one thing that remains is the Word of God and it stands forever. He is coming and and the nations shall discover they are as a drop in bucket. They will faint and lose heart as they begin to understand that it is God Himself that stretches out the heavens like a curtain. He brings the proud and elite men of this world to nothing. The Lord blows upon them and they wither in the whirlwind and are taken away like stubble in the wind. Yet to those who walk along the highway of Holiness, He increases their strength. He dwells with the lowly of heart and renews them. They shall run and not grow weary, they shall walk and not faint and they indeed shall rise up with wings like eagles and fly to the high and holy place where the spirit of the humble is revived.