Thy son shall no more go down, neither shall thy moon withdraw itself: for the Lord shall be thine everlasting light, and the days of thy mourning shall be ended.
The sun and moon will not be noticed as rising and setting, in Jerusalem, due to the fact that God’s Glory will be the light of this city both day and night, and this will be brighter than the light of the sun and moon [v20; Isaiah 4:5-6].
True source of light: The idea here is not that there will not be any sun and moon, but simply that they will not be the source of light for the earthly Jerusalem [v19-20]; Isaiah 4:4-6].
There will not be a need for the sun and moon eternally in other parts of the earth [Isaiah 30:26].
The same idea is true concerning the New Jerusalem when it comes down to the new earth – the inhabitants will have no need of the sun and moon to light that city, for God’s glory will be the light of it [Rev. 21:23].
The sun and moon will always be needed for the earth, but not in these 2 cities – the earthly and heavenly Jerusalems.
– Dake A.R. Bible : Page 745.