24 For all flesh is as grass, and all the glory of man as the flower of grass. The grass withereth, and the flower thereof falleth away: 25 But the word of the Lord endureth for ever. And this is the word which by the gospel is preached unto you. (1 Peter 1:24-25 KJV)
The Enduring Word
The apostle, having explained the excellence of the renewed spiritual person as being born again—not of corruptible but incorruptible seed—now shows the vanity of the natural man, even with all his outward advantages: “For all flesh is as grass, and all the glory of man as the flower of grass” (1 Peter 1:24). Nothing can make him truly substantial except being born again through the incorruptible seed, the word of God, which transforms him into a far better being, whose glory will not fade like a flower but shine like an angel. This word is presented to you daily in the preaching of the gospel. Learn,
Man, at his peak of success and glory, is still a fading, dying creature. Taken individually, all flesh is grass—in birth, in life, and in death, he is like grass (Job 14:2; Isaiah 40:6-7). Even in all his glory—his wit, beauty, strength, wealth, and honor—he is still like the flower of grass, which quickly withers and dies.
The only way for this perishing creature to become solid and incorruptible is to accept and receive the word of God. This word remains eternal truth and, when received, preserves him for eternal life and stays with him forever. The prophets and apostles preached the same doctrine. The word delivered by Isaiah and others in the Old Testament is the same as what the apostles preached in the New.