The Word that abides forever, even after the flower and grass fades, is the Gospel, the good news of Jesus Christ. The Gospel is that the Kingdom of God has arrived (Mark 1:15). It is that Jesus is Lord (Romans 10:9), the King of the kingdom, and the Lord of all people, the Lord of heaven and earth. He is not some “tribal Lord”; He is Lord of all by right of creation and redemption. He is Lord of all as the pre-incarnate Cosmic Universal Christ. He is the Word made flesh (John 1:14). He is the Word; He is what God has to say about Himself. He is God speaking to us. He is the living and abiding Word Who is “the image of the invisible God” (Colossians 1:15). He is the good news; He is the Word we are to preach.
“Since you have been born again, not of perishable seed but of imperishable, through the living and abiding word of God; for “All flesh is like grass and all its glory like the flower of grass. The grass withers, and the flower falls, but the word of the Lord remains forever.” And this word is the good news that was preached to you.” (1 Peter 1:23–25 ESV)