The Spirit of the Lord; or, the breath, &c, as this word is rendered, Psalms 147:18; the wind, as it frequently signifies, which hath this effect upon grass and flowers, Psalms 103:16 James 1:11. The people; the same which he called flesh, and said they were grass, Isaiah 40:6; which, that he might prove, in this verse he first declares the frail nature of grass and flowers, and then he applies this to the people. Or, this people; the Jews no less than the Gentiles; for here is an article in the Hebrew text, which is frequently emphatical and restrictive.
Related Commentaries of Isaiah 40:7
Isaiah 40:7
7 The grass withereth, the flower fadeth: because the spirit of the LORD bloweth upon it: surely the people is grass.