Why will there be walls around the new Jerusalem?

from the old testament

• The walls around the New Jerusalem are not mentioned in the Old Testament.

from the new testament

• The New Jerusalem will come after the millennium, Christ’s 1,000-year reign on earth (Revelation 20:4–6), and the final judgment, when God will create a new heaven and a new earth (Revelation 21:1–2). It will descend from heaven as the eternal dwelling place of God with His redeemed people, after sin, death, and Satan are fully defeated (Revelation 20:10–15; 21:3–4).
• In his vision of the New Jerusalem, John stated, "It had a great, high wall, with twelve gates, and at the gates twelve angels, and on the gates the names of the twelve tribes of the sons of Israel were inscribed—on the east three gates, on the north three gates, on the south three gates, and on the west three gates. And the wall of the city had twelve foundations, and on them were the twelve names of the twelve apostles of the Lamb" (Revelation 21:12–14).
• While not every detail about these walls is provided, some aspects are clear. First, the walls will display the greatness of the Lord. Revelation 21:15–21 notes the enormous size of the walls, about 1,380 miles long on each side, as well as in height. It measured 144 cubits, likely describing its thickness of approximately 216 feet or 72 yards.
• Second, the details of the walls demonstrate the unmatched riches of the Lord. Revelation 21:18–20 describes them as made of precious jewels.
• Third, the walls include the names of the twelve tribes of Israel and twelve apostles, representing the New Jerusalem as the home of those who follow the Lord (Revelation 21:12–14). The twelve tribes of Israel were the descendants of Abraham, Isaac, and Jacob who lived by faith in the Lord (see Genesis 12:1–3; Hebrews 11:8–16). The apostles represent those who believe in Jesus as Messiah (Matthew 16:18; Revelation 21:14).
• Fourth, the walls will also stand as a symbol of beauty. The chapter uses the analogy of the bride coming to meet the groom for the wedding. The description of the city reveals the most beautiful of materials. Those who dwell there will enjoy the greatest surroundings, a stark contrast from the lake of fire, where those whose names are not found in the book of life will dwell (Revelation 20:15).

implications for today

While not every detail about this future city and its walls is described, those that are provided clearly show a place very desirable for living. John's vision emphasizes the greatness of this future heavenly city, where God's people will dwell with Him forever. The high walls of the New Jerusalem symbolize the distinction between the holy city and the rest of creation, marking it as a place set apart for God's presence. In Revelation 21:27, it is stated that "nothing unclean will ever enter it," indicating that the city is reserved exclusively for the righteous—those whose names are written in the Lamb's book of life. This serves as a clear boundary. The walls emphasize God's holiness and the purity of the eternal kingdom, free from sin and corruption. The city is not just a physical structure, but a reflection of the perfect righteousness of God, where His people can dwell in unbroken fellowship with Him.

The walls also represent the ultimate victory of God over sin, evil, and death. They serve as a protective barrier, ensuring that nothing defiled can enter the city and that the redeemed can live securely in God's presence forever. This separation signifies the fulfillment of God's promise to restore His people and create a perfect, holy dwelling place for them. The walls of the New Jerusalem are a powerful reminder of God's sanctifying work and the eternal safety and purity of His eternal home.