The following is an excerpt from The MacArthur New Testament Commentary on Revelation 21.

and they will bring the glory and the honor of the nations into it; and nothing unclean, and no one who practices abomination and lying, shall ever come into it, but only those whose names are written in the Lamb’s book of life.(21:26–27)

Then John adds another detail to his description of the New Jerusalem. Throughout the never-ending daytime of the eternal state (for there will be no night there) its gates will never be closed. In an ancient walled city, the gates were closed at nightfall to keep invaders, marauders, criminals, and other potentially dangerous individuals from entering the city under cover of darkness. That there will be no night in eternity, and the gates of the New Jerusalem will never need to be closed, depicts the city’s complete security. It will be a place of rest, safety, and refreshment, where God’s people will “rest from their labors” (14:13).

The kings will not be the only ones to surrender their earthly prestige and glory when they enter heaven. The glory and the honor of the nations will also dissolve, as it were, into the eternal worship of God the Father and the Lord Jesus Christ. Like the twenty-four elders, all who enter heaven “will cast their crowns before the throne” of God (4:10).

All in heaven will be perfectly holy. Thus, nothing unclean, and no one who practices abomination and lying, shall ever come into the New Jerusalem (see the discussions of 21:7–8 in chap. 18 of this volume and 22:15 in chap. 21). The only ones there will be those whose names are written in the Lamb’s book of life. (For a discussion of the book of life, see 3:5; 13:8; and the comments on 20:12 in chap. 17 of this volume.)