Isaiah 40:3-5
New King James Version (NKJV)

3 The voice of one crying in the wilderness:
“Prepare the way of the Lord;
Make straight in the desert
A highway for our God.
4 Every valley shall be exalted
And every mountain and hill brought low;
The crooked places shall be made straight
And the rough places smooth;
5 The glory of the Lord shall be revealed,
And all flesh shall see it together;
For the mouth of the Lord has spoken.”