The nation of Israel was God’s kingdom upon the earth. God through Samuel anointed David king. David reigned in Jerusalem After David, Solomon reigned in Jerusalem.
The throne of David in Jerusalem was the throne of the LORD
1 Chronicles 29:23 Then Solomon sat on the throne of the LORD as king instead of David his father, and prospered; and all Israel obeyed him.
In the last days, David’s throne will be restored as the throne of the Lord in Jerusalem.
Jeremiah 3:17 At that time they shall call Jerusalem the throne of the LORD; and all the nations shall be gathered unto it, to the name of the LORD, to Jerusalem: neither shall they walk any more after the imagination of their evil heart.
Jesus Christ is the king who will sit upon David’s throne when he returns to judge the world.
Luke 1:32 He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David: 33 And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end.
Jesus will rule over the mortal population of the earth from the throne of David in Jerusalem for 1000 years.
Isaiah 2:1 The word that Isaiah the son of Amoz saw concerning Judah and Jerusalem. 2 And it shall come to pass in the last days, that the mountain of the LORD’S house shall be established in the top of the mountains, and shall be exalted above the hills; and all nations shall flow unto it. 3 And many people shall go and say, Come ye, and let us go up to the mountain of the LORD, to the house of the God of Jacob; and he will teach us of his ways, and we will walk in his paths: for out of Zion shall go forth the law, and the word of the LORD from Jerusalem. 4 And he shall judge among the nations, and shall rebuke many people: and they shall beat their swords into plowshares, and their spears into pruninghooks: nation shall not lift up sword against nation, neither shall they learn war any more.
I hope this helps.