Revelation 21:27Meaning & Commentary from the Church Fathers

[...] But nothing defiled or unclean will enter there, for what fellowship has light with darkness? (2 Cor 6:14).

It is true that no one enters this assembly of the saints who either refused to be cleansed from former sin and ancestral guilt, or, after being cleansed, became defiled and refused to wash himself in the bath of humility and the stream of tears. Indeed, the Jew or heretic commits abomination, for he falsely worships God. Only those are said to enter who are written in the Lamb's book of life, that is, those whom true faith and firm hope embrace.

Here he describes the Church of the age to come, when sinners will not be mingled with the righteous as they are now, nor permitted to dwell with them. For the righteous are governed by Christ alone. With Him and in Him they will abide blessedly in that heavenly Jerusalem, the mother of all. He says, of course, that they are written in the book of that Lamb who said, "Rejoice that your names are written in heaven" (Lk 10:20).

The gates of the Kingdom of Heaven, once opened by Christ, will remain open forever for all the nations being saved. All who have pleased Christ, all who are written in the book of life, will enter the Kingdom of Heaven. But for everything unclean and defiled, for vicious and corrupt people, the gates of the Kingdom of Heaven are closed. They are closed to those who neglect faith, truth, and the holiness of God’s laws. They are closed to those who give creation the honor that belongs to God alone, and who confess and preach false teachings and errors. St. Andrew speaks thus about the gates always being open and the absence of night in the holy city: “There will be day there, and not night, for night will be set apart for sinners.”

By what features is the inner life of the inhabitants of the heavenly city described? This means that heavenly religion is wholly spiritual and without rites. There the one pure and unveiled truth will be directly received and known by all. There will be no need of a material temple, because worship will be offered directly to the Lord God in the living image of His Son, the Lord Jesus Christ. Secondly, the heavenly city needs no illumination, for the glory of God illumined it, and its lamp is the Lamb; cf. Isa 60:19. This means that every member of the Church of God in heaven will be wholly embraced by the Spirit of God. Each will be abundantly illumined by the light of the knowledge of God and of the glory of God.

Do you desire blessedness? For this you need righteousness, or virtue. “Nothing unclean shall enter” the blessed city of God, “nor anyone who practices abomination and falsehood” (Rev 21:27). Eternal life can be possessed only by those who have fulfilled the commandments of God: “The man who does them shall live by them” (Gal 3:12). So it must be according to the righteousness of the living God. It would not be fitting for Him to admit the disobedient, and those resisting His will, into communion with His own eternal life. I say His own life, for “He alone has immortality” in the proper sense (1 Tim 6:16). All other beings have life and immortality only by participation in His life and blessedness. So it must be according to the very nature of eternal life.