The prophet calls the people to repentance, justice, compassion and worship. In the midst of spiritual confusion and moral dissonance the faithful must remain steadfast. This vision of a new heaven and a new earth fosters hope, and it elicits incisive action. Vision looks inward and becomes duty. Vision looks outward and becomes aspiration.
Vision looks upward and becomes faith.
If God transcendent offers us a vision, it is the incarnation that is the reason for hope. The incarnation - God entering into human life so that we might enter into the life of God. The incarnation of God in human flesh is the defining mystery of Christian life and faith, wherein God and humanity, two spheres of existence, meet in wondrous exchange. We must believe in the full humanity of Jesus, or we lose the One who experienced and understands the human condition. His sacrifice upon the cross - his death would be meaningless were he divine only.