I have a question about the Millennium . Will Jesus reign from the earthly Jerusalem or from the New Jerusalem for those 1,000 years?
I think the answer is in Rev. 22:3
The throne of God and of the Lamb will be in the city, and his servants will serve him.
This tells us the throne of the Lamb (Jesus) will be in the holy city. We know it’s on Earth because Rev. 22:1-2 says the great river and the tree of life for the healing of the nations are also in the holy city. These are mentioned in Ezekiel 47 as being on Earth.
I believe the reference to His servants serving Him could relate to the tribulation martyrs of Rev. 7 whose destiny is to serve the Lord in His Temple. There is no temple in the New Jerusalem.