“Let every valley be lifted up, And every mountain and hill be made low; And let the rough ground become a plain, And the rugged terrain a broad valley; Then the glory of the LORD will be revealed, And all flesh will see it together; For the mouth of the LORD has spoken.”
Isaiah 40:4-5 NASB
The land will be flattened so there will be no obstacle to seeing the glory of the Lord. No one will be in a valley so low that they can't see out. No one will be so high that they look down on the Almighty. God makes Himself available to all, so we may approach His throne with joy and boldness.
God is clearing away obstacles that lie between Him and the people that would be joined together with Him in a relationship of love. We are to do our part in clearing away the obstacles that lie along that same pathway.