Isaiah 40:6

The voice said, "Cry out!" And he said, "What shall I cry?" "All flesh is grass, And all its loveliness is like the flower of the field.

Surrounding context

40:5 The glory of the LORD shall be revealed, And all flesh shall see it together; For the mouth of the LORD has spoken."

40:6 The voice said, "Cry out!" And he said, "What shall I cry?" "All flesh is grass, And all its loveliness is like the flower of the field.

40:7 The grass withers, the flower fades, Because the breath of the LORD blows upon it; Surely the people are grass.

Translation and sources