Its lamp is the Lamb

9 Then came one of the seven angels who had the seven bowls full of the seven last plagues and spoke to me, saying, “Come, I will show you the Bride, the wife of the Lamb.” 10 And he carried me away in the Spirit to a great, high mountain, and showed me the holy city Jerusalem coming down out of heaven from God, 11 having the glory of God, its radiance like a most rare jewel, like a jasper, clear as crystal. 12 It had a great, high wall, with twelve gates, and at the gates twelve angels, and on the gates the names of the twelve tribes of the sons of Israel were inscribed— 13 on the east three gates, on the north three gates, on the south three gates, and on the west three gates. 14 And the wall of the city had twelve foundations, and on them were the twelve names of the twelve apostles of the Lamb.

15 And the one who spoke with me had a measuring rod of gold to measure the city and its gates and walls. 16 The city lies foursquare, its length the same as its width. And he measured the city with his rod, 12,000 stadia. Its length and width and height are equal. 17 He also measured its wall, 144 cubits by human measurement, which is also an angel's measurement. 18 The wall was built of jasper, while the city was pure gold, like clear glass. 19 The foundations of the wall of the city were adorned with every kind of jewel. The first was jasper, the second sapphire, the third agate, the fourth emerald, 20 the fifth onyx, the sixth carnelian, the seventh chrysolite, the eighth beryl, the ninth topaz, the tenth chrysoprase, the eleventh jacinth, the twelfth amethyst. 21 And the twelve gates were twelve pearls, each of the gates made of a single pearl, and the street of the city was pure gold, like transparent glass.

22 And I saw no temple in the city, for its temple is the Lord God the Almighty and the Lamb. 23 And the city has no need of sun or moon to shine on it, for the glory of God gives it light, and its lamp is the Lamb. 24 By its light will the nations walk, and the kings of the earth will bring their glory into it, 25 and its gates will never be shut by day—and there will be no night there. 26 They will bring into it the glory and the honor of the nations. 27 But nothing unclean will ever enter it, nor anyone who does what is detestable or false, but only those who are written in the Lamb's book of life (Rev 21).

Then the angel showed me the river of the water of life, bright as crystal, flowing from the throne of God and of the Lamb 2 through the middle of the street of the city; also, on either side of the river, the tree of life with its twelve kinds of fruit, yielding its fruit each month. The leaves of the tree were for the healing of the nations. 3 No longer will there be anything accursed, but the throne of God and of the Lamb will be in it, and his servants will worship him. 4 They will see his face, and his name will be on their foreheads. 5 And night will be no more. They will need no light of lamp or sun, for the Lord God will be their light, and they will reign forever and ever (Rev 22:1-5).

i) I doubt the world to come will actually be devoid of oceans, sunlight and moonlight. Rather, that describes the visionary world John saw, like a surreal dreamscape. Dreams can have a detailed geography internal to the dream, but that doesn't correspond to reality outside the dreamscape. And visions are like inspired daydreams. 

ii) One exegetical question is the extent to which these are picturesque metaphors or direct descriptions of what John saw. In reading Revelation, it's useful to assume the viewpoint of a director. If you were filming Revelation, how would you visualize the imagery?

iii) Apropos (ii), John depicts the New Jerusalem as a fortified city. He says the source of illumination wasn't natural lighting but the Father and the Son. What is the reader supposed to envision? If these are figures of speech, then they don't necessarily depict a unified pictorial composition. If, however, these are descriptions of what John saw in his vision, then how should the reader imagine the scene?

Is the supernatural illumination external lighting? Does it shine over the city? Or is it interior lighting? Rev 1 begins with a Christophany. Jesus appears to John. His appearance is luminous. In addition to his personal radiance, he's holding a menorah. 

We have other examples of supernatural divine illumination in Scripture. The Shekinah. The pillar of fire. The Star of Bethlehem. So it's possible that John saw something like that. Perhaps, then, there's light within the new Jerusalem, but darkness outside the city walls. The source of light is not above the city, but inside the city. 

iv) Before the advent of electrical lighting, it was generally brighter outside than inside. During the day, exterior lighting (sunlight) illuminated buildings, through an open door, window, or oculus (like the Roman Pantheon). 

But in churches, the situation was reversed at night. After dark, candlelight made churches brighter on the inside than the outside. At night, a parishioner was walking into the light, as he entered church. Instead of sunlight illuminating the interior through windows, the widows radiated candlelight. Against the backdrop of the night, you could see the church as a literal beacon of light. A symbolic lighthouse.

v) One time during a power outage, I went outside while it was still light out. The only available light was sunlight, and that was fading by inches. 

Probably most folks in a hitech civilization have never watched daylight gradually fade until the last glimmering of light is gone. We have electrical lighting, flashlights, camp lanterns. We usually have some backup lighting source that we switch to before we're plunged into darkness. If there's a sudden blackout, we may grope in the dark for flashlights, but that's because we were caught off-guard. For obvious reasons, we don't normally wait until we can't see anything to reach for a flashlight. 

But imagine a traveler in the ancient world heading for a fortified city. Back then, a unit of time was "day's journey". You had to time things. Imagine the traveler's panic as he sees that he's running out of time before nightfall. He won't make it to the city in time. He clings to the remaining, fading daylight. After sunset there's some residual ambient light, but that's bleeding out–orange, red, gray, black. Now he's lost in the dark. At the mercy of nocturnal predators. 

And that's a description of hell. Outer darkness. Outside the city gates. Overtaken by the night. Eternal darkness. 

Consider the reverse. When God created light, when he said, "Let there be light!", was there a sudden burst of light, or was it like a dimmer? An imperceptibly incremental brightening, like sunrise?