What Does Isaiah 40:6 Mean?

Having set the horizon of glory before the exiles, Isaiah turns to the weakness of the human recipients of that promise. The command to cry and the question about what should be proclaimed introduce prophetic realism into the chapter's comfort. Babylon's victims were not sturdy candidates for restoration. They were frail, mortal, and historically fragile. Isaiah therefore addresses the problem that always shadows redemption in a fallen world: how can lasting hope be spoken to a people whose life collapses as quickly as field growth under harsh conditions?

By naming all flesh as grass, the prophet strips away every illusion of human durability. Beauty, vigor, and national strength fade with alarming speed when measured before the Holy One. This is part of the theology of the remnant. God does not save a people because they possess hidden reserves of power. He saves those who learn that creaturely life cannot secure covenant promises by itself. Comfort becomes truthful only when human weakness is admitted fully. Hope rests in God precisely because man is not enough.

Christ answers this human frailty by entering it without succumbing to its corruption. He takes real flesh, shares the mortality Isaiah exposes, and then carries that mortal life through death into resurrection. Peter later places this Isaianic contrast beside the Gospel because Jesus alone can give imperishable life to withering people. The Savior does not flatter human strength. He rescues grasslike humanity by uniting it to His own risen life.