This prophecy speaks of a time in the future after the Tribulation when Jesus shall descend upon the Earth and a great glory will fill and cover all of Zion (ie, Israel), and especially Jerusalem.  It will be a time of unbelievable prosperity, blessing, glory and wonder.  People of every nation will come up to Jerusalem to worship the Lord.  The new temple will be there, and will replace the defiled and desecrated 3rd temple, and Jesus will sit on the throne of David ruling the entire world from there.