How long will David's kingdom and throne last?

David's house, kingdom, and throne shall be established forever. This is not merely a thousand years but forever. His royal line begins with David, continues through Solomon, and extends all the way to the Messiah, Christ Himself, whose throne is established forever.

Les explains that the term "house of David" refers to that royal family beginning with David and then carried on through Solomon all the way down to the Messiah Christ Himself. He emphasizes that God's promise is that David's house and kingdom shall be established forever—not a thousand years, forever—and thy throne shall be established forever. Les therefore feels that the whole millennial economy will go right on into the eternal state. He connects this to Revelation 22, where the nations continue with Israel as the head of the nations, Christ as the King of kings and Lord of lords, no more curse, and the throne of God and of the Lamb in the midst, with believers from the ages seeing His face.

Is David's kingdom established for a thousand years or forever?

The promise declares David’s house and kingdom are established forever, not merely for a thousand years. The throne is established forever. The millennial economy is described as continuing into the eternal state, with Israel as head of the nations and Christ as King of kings and Lord of lords.