What does the Bible say about the two-fold message of the voice?

In Isaiah 40, the prophet Isaiah conveys a crucial two-fold message through the voice of John the Baptist. First, he declares that 'all flesh is grass', highlighting the transience and vanity of human life compared to the eternal word of God. This serves as a warning for people to recognize their sinful, fleeting nature and the urgency of repentance. Second, he commands people to 'behold your God', proclaiming the good news of God's salvation and the coming of Jesus Christ, who is the only way to God. These messages remind believers of their need for humility and faith in the divine.