A.T. Robertson Commentary Revelation 21:24

"And the nations shall walk amidst the light thereof: and the kings of the earth bring their glory into it." — Revelation 21:24 (ASV)

Amidst the light thereof (δια του φωτος αυτης). Rather "by the light thereof." From Isa 60:3, 11, 20. All the moral and spiritual progress of moderns is due to Christ, and the nations of earth will be represented, including "the kings" (ο βασιλεις), mentioned also in Isa 60:3, "do bring their glory into it" (φερουσιν την δοξαν αυτων εις αυτην). Present active indicative of φερω. Swete is uncertain whether this is a picture of heaven itself or "some gracious purpose of God towards humanity which has not yet been revealed" and he cites 22:2 in illustration. The picture is beautiful and glorious even if not realized here, but only in heaven.