New Jerusalem is in heaven. Each time the Bible mentions New Jerusalem, it is said to come down from heaven, where angels guard the city’s gates. (Revelation 3:​12; 21:​2, 10, 12) Also, the city’s great size proves that it could not be on earth. It is a cube measuring “12,000 stadia,” or “furlongs,” around. a (Revelation 21:16; King James Version) Its sides would thus be almost 560 kilometers (350 mi) high, extending into space.

New Jerusalem is depicted as “coming down out of heaven from God,” showing that God uses it to affect matters outside of heaven. (Revelation 21:2) This expression links New Jerusalem with God’s Kingdom, which God uses to accomplish his will “as in heaven, also on earth.” (Matthew 6:​10) God’s purpose for people on earth includes these blessings:

Removal of sin. “A river of water of life” flows from New Jerusalem and supports “trees of life” that are “for the healing of the nations.” (Revelation 22:​1, 2) This physical and spiritual healing will remove sin and enable people to gain perfect life, as God originally intended.​—Romans 8:​21.

Good relations between God and humankind. Sin has alienated humans from God. (Isaiah 59:2) The removal of sin will allow for the complete fulfillment of this prophecy: “The tent of God is with mankind, and he will reside with them, and they will be his people. And God himself will be with them.”​—Revelation 21:3.

The end of suffering and death. By means of his Kingdom, God “will wipe out every tear from their eyes, and death will be no more, neither will mourning nor outcry nor pain be anymore.”​—Revelation 21:4.