"Just as Jehovah's Shekinah light illuminated the Most Holy of the ancient tabernacle and temple, so his glory directly lights up the New Jerusalem. Ancient Babylon on the Euphrates River needed oil lamps for lighting at night; but, if there were any night around the heavenly New Jerusalem, the Lamb of God would be its lamp. This explains why 'the city has no need of the sun nor of the moon to shine upon it.' But men on earth will need such lights. The invisible heavenly city will shed a spiritual light upon the inhabiters of the 'new earth.' A complete clarification of the Bible will be given to them, together with all the righteous, enlightening, guiding rules, laws and instructions that will be given to them. So the nations on earth, that is, those not of the 144,000 spiritual Israelites, will walk in the spiritual light coming from the city and will see how to walk in the way that leads to everlasting life without stumbling. All the families and nations of the earth will thus be blessed. — Genesis l2:3; 22:18."
"Babylon the Great Has Fallen", pages 660-1.