Isaiah 40:3-5

The voice of one shouting in the wilderness, Prepare the way of the Lord, Make His paths straight.  Every ravine shall be filled up, and every mountain and hill shall be leveled; and the crooked (places) shall be made straight, and the rough roads smooth; and all mankind shall see the salvation of God.

The promise from God through Isaiah, spoken roughly 2,756 years ago, is the plan for our salvation and the coming of Jesus. Our part is to pray, believe in the word in faith, and act upon it.  We are to cleanse our hearts and renew our minds and be the vessels of the word that God needs us to be.