1 Peter 1:22-25

Since you have purified yourselves by your obedience to the truth, so that you show sincere brotherly love for each other, from a pure heart love one another constantly, because you have been born again  — not of perishable seed but of imperishable — through the living and enduring word of God. For All flesh is like grass, and all its glory like a flower of the grass. The grass withers, and the flower falls, but the word of the Lord endures forever. And this word is the gospel that was proclaimed to you.