To shine upon it (ινα φαινωσιν αυτη). Purpose clause with ινα and the present active subjunctive of φαινω, to keep on shining. Light is always a problem in our cities. See Isaiah 60:19.

Did lighten it (εφωτισεν αυτην). First aorist active indicative of φωτιζω, to illumine, old verb from φως (Luke 11:36). If the sun and moon did shine, they would give no added light in the presence of the Shekinah Glory of God. See verse Revelation 21:11 for "the glory of God." Cf. Revelation 18:1; Revelation 21:3. "Their splendour is simply put to shame by the glory of God Himself" (Charles).

And the lamp thereof is the Lamb (κα ο λυχνος αυτης το αρνιον). Charles takes ο λυχνος as predicate, "and the Lamb is the lamp thereof." Bousset thinks that John means to compare Christ to the moon the lesser light (Genesis 1:16), but that contrast is not necessary. Swete sees Christ as the one lamp for all in contrast with the many λυχνια of the churches on earth (Revelation 1:12; Revelation 1:20). "No words could more clearly demonstrate the purely spiritual character of St. John's conception of the New Jerusalem" (Swete).

Rev 21:24

Amidst the light thereof (δια του φωτος αυτης). Rather "by the light thereof." From Isaiah 60:3; Isaiah 60:11; Isaiah 60:20. 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 Isaiah 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 Revelation 22:2 in illustration. The picture is beautiful and glorious even if not realized here, but only in heaven.