Isaiah 40:3-8

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: and the glory of the LORD shall be revealed, and all flesh shall see it together: for the mouth of the LORD hath spoken it.
The voice said, Cry. And he said, What shall I cry? All flesh is grass, and all the goodliness thereof is as the flower of the field: the grass withereth, the flower fadeth: because the spirit of the LORD bloweth upon it: surely the people is grass. The grass withereth, the flower fadeth: but the word of our God shall stand for ever.