In many ways, the kingdoms of David and Solomon fulfill the promises God has given to Abraham, Isaac, Jacob, and the 12 tribes of Israel, concerning people, land, and blessing. A good summary of this can be found in 1 Kings 4.

The life of David serves as a foreshadowing of Christ - a King God chose and anointed, who faithfully seeks after God's heart, who must endure a period of suffering and trial before He's vindicated and sits upon the Throne He was promised. In 2 Samuel 7, the Lord declares to David that through his line a mighty King will come who will sit upon David's throne. This King will be known as the Son of God, and His Kingdom will have no end.

In the immediate, Solomon fulfills one aspect of what God declares to David: Solomon builds a house for the Lord, God calls Solomon His son, Solomon is a mighty king. Yet, by the end of Solomon's reign, it's clear that he's not the total fulfillment of what God has promised; a greater King than Solomon is needed and longer for.