The Lamb is the Light!
And I saw no temple therein: for the Lord God Almighty and the Lamb are the temple of it. And the city had no need of the sun, neither of the moon, to shine in it: for the glory of God did lighten it, and the Lamb is the light thereof. (Revelation 21:22, 23)
God lights the new creation directly by His presence. After the entrance of sin into the old creation, God withdrew His presence, and "darkness was upon the face of the deep" (Genesis 1:2). Then God made use of the physical lights in His universe. He put them up like we put up street lights or lights in our homes. However, in the new creation sin is removed, and He again becomes the source of light. Today the Lord Jesus Christ is the Light of the World in a spiritual sense: "Then spake Jesus again unto them, saying, I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life" (John 8:12).
In the new creation, He is the direct physical as well as the spiritual light. In the tabernacle there was the golden lampstand, which is one of the finest pictures of Christ. In the New Jerusalem, He is the golden lampstand. The nations of the world will enter the Holy City as the priests entered the Holy Place in the tabernacle for the purpose of worship. The nations of the earth, as well as Israel, will come to the New Jerusalem as the high priest of old entered the Holy of Holies. Instead of the blood being brought, the Lamb is there in person.
The temple, which supplanted the tabernacle back in the nation Israel, was an earthly enclosure for the shekinah glory. It was a testimony to the presence of God and the presence of sin. Where sin existed, God could be approached only by the ritual of the temple. However, in the New Jerusalem sin is no longer a reality but is like a hideous nightmare, even locked out of the closet of memory. The actual presence of God with the redeemed eliminates the necessity for a temple, although the whole city may be thought of as a temple. In the city of light, God is present and sin is absent; therefore, an edifice of a material substance is no longer necessary, The physical temple was a poor substitute for the presence of God. The New Jerusalem possesses the genuine article – God in person. It is probably the first place where God will make a personal appearance before man. What a glorious prospect this is!
New Jerusalem will be independent of the sun and moon for light and life. What a contrast to the earth, which is utterly dependent upon them. It may be that the sun and moon will even be dependent upon the celestial city for power to transmit light, since the One who is the source of light and life will dwell within the city. Neither will light be furnished by the New Jerusalem Light and Power Company. The One who is light will be there, and the effulgence of His glory will be manifested in the New Jerusalem unhindered.
From Edited Messages on Revelation by J. Vernon McGee