Esias 40:6

6 The voice of one saying, Cry; and I said, What shall I cry? All flesh is grass, and all the glory of man as the flower of grass:

Esias 40:6 In-Context

4 Every valley shall be filled, and every mountain and hill shall be brought low: and all the crooked shall become straight, and the rough plains.
5 And the glory of the Lord shall appear, and all flesh shall see the salvation of God: for the Lord has spoken .
6 The voice of one saying, Cry; and I said, What shall I cry? All flesh is grass, and all the glory of man as the flower of grass:
8 The grass withers, and the flower fades: but the word of our God abides for ever.

The Brenton translation of the Septuagint is in the public domain.