Isaiah 60: 1-3.
Arise, shine; for thy light is come, and the glory of the Lord is risen upon thee.
2 For, behold, the darkness shall cover the earth, and gross darkness the people: but the Lord shall arise upon thee, and His glory shall be seen upon thee.
3 And the Gentiles shall come to thy light, and kings to the brightness of thy rising.

The Light of Israel in the Millennium and New Earth period will be the glory of God. The same will be true for the inhabitants of Jerusalem (Rev. 21:23).
Darkness will literally cover the earth just before the appearance of the the glory of God at the 2nd advent of Christ, making the glory appear more glorious as it expels the darkness which will come by the darkening of the sun, moon, and stars (13:10; Joel 3:15; Matt. 24:29, Acts 2:20). We must not understand darkness as being spiritual, but literal where it is clear, as in these passages. Surely there will be spiritual darkness as Antichrist throws his power over the earth, but there will also be a literal darkness, unexplainable to the human mind. Perhaps some will say it is global warming 🙂
“His glory” in v. 2 is the same as the light in v. 1.
So great and so beautiful will be the light in Israel that it will attract the Gentiles from all nations, including the rulers of the Gentile nations.
The earth will have gone through the horrors of the Tribulation period. Hundreds of thousands will have died for their faith. The darkness will seem all-consuming, and impenetrable. And then——the glory of God will burst upon Israel and Jerusalem, and people from all around the world will be drawn to the Light.
What an exciting time that will be!