Here are some commentary
Aquinas Study Bible- New Jerusalem, that is, the unified society of the elect perfected by love. New in relation to the glory of their bodies. For the bodies of the saints which are corruptible in quality. Coming down out of heaven, that is, from the highest heaven, so that they may put on their bodies and appear for the judgment. (Nicholas of Lyra)
Haydock Bible- Coming down from God out of heaven. By the city we must understand its citizens, the Angels and saints. (Witham) — Justice, innocence, the good works of the saints, are the ornaments of the inhabitants of this new Jerusalem, the Church triumphant. If the world of the old Adam has appeared so beautiful, so magnificent, good God, what will be the riches of that which is made for Jesus Christ, the second Adam, and for his members! O Jesus! Father of the world to come, render us worthy of this new and everlasting world, and give us a disgust, a mortal hatred, for that which perishes, and which is the cause of our perdition.
My personal commentary on Revelation- This holy city , the New Jerusalem, is the Church in glory. She comes down as a bride since she will be in Her fullness and fully prepared to be fully united to Christ with all Her members in a glorified state. Even though God dwells with man now in the Church, he will be more united with man because sin will no longer exist among the people of God.
