Isaiah 9:7. “Of the increase of His government and peace there shall be no end, upon the throne of David, and upon His kingdom, to order it, and to establish it with judgment and with justice from hence forth even for ever. The zeal of the Lord of hosts will perform this.”
When Jesus returns to establish His kingdom, the world finally experience the peace that so many are crying for today. The difference will be that no human ruler will be in charge. Jesus Christ Himself will sit on the throne of David, and the extent of His government, and the peace He will create, will have no end. This, by the way, is what a much loved Christmas carol is actually about: Not His birth, but His return as King of King and Lord of Lords.
When Jesus establishes Himself on the throne of Dave, 2 Sam. 7:16 will be fulfilled. His judgment and righteousness will never end.
One of my sources indicates that the word zeal in this passage would better be rendered as jealousy. W.E Vine says:
His jealousy will have two goals. It is a fire of indignation against all who mistreated His chosen earthly people; it is also a fire that burns with such a love for them and zeal for their welfare that it must consume all unfaithfulness in their midst.