Isaiah 40:6

קוֹל אֹמֵר קְרָא וְאָמַר מָה אֶקְרָא כָּל-הַבָּשָׂר חָצִיר וְכָל-חַסְדּוֹ כְּצִיץ הַשָּׂדֶה

6 A voice saying, "Cry out!," and he [I] said, "What shall I cry?" "All flesh is grass, and all their glory is like the flowers of the field."

קוֹל אֹמֵר קְרָא A voice saying, "Cry out!," Once again, the speaker goes unidentified. The qal active participle אֹמֵר does not drop us into any particular time or scene. A qal imperative, קְרָא, is the same form given in the earlier commands.

וְאָמַר מָה אֶקְרָא  and he [I] said, "What shall I cry?" The apparatus of BHS presents וָאֹמַר "And I said" as a variant reading based on the Greek and Vulgate. The Isaiah Scroll from Qumran has וָאוֹמְרָה, the qal vav-consecutive imperfect 1 sg (with interior waw-holem) to support the reading as well. If the MT is correct, we might point out that Isaiah might not actually see himself in the vision, even though he himself answered the cry, as he did in chapter 6.

כָּל-הַבָּשָׂר חָצִיר  "All flesh is grass, Nominal sentence without a comparative preposition; simply a statement: Flesh is grass. There is nothing permanent or lasting or even strong about grass. Grass is as vivid a word as "oak" (Isaiah 61:3) but for the opposite reason.

וְכָל-חַסְדּוֹ כְּצִיץ הַשָּׂדֶה and all their glory is like the flowers of the field." Usually the word חֶסֶד means "mercy, grace" of "favor" from a root idea of "obligation to community" (Holladay). But this isn't God's action; it's ours: Our grace, the grace we have from within (which is not the grace of God) doesn't benefit us anything at all. It's like flowers out in the field; few people see them, and fewer still think they're pretty. An Mp note tells us that כְּצִיץ "like the flowers" occurs three times: Job 14:2; Psalm 103:15, and here in Isaiah 40:6.