2 Samuel -- the Davidic covenant

When your days are fulfilled and you lie down with your fathers, I will raise up your offspring after you, who shall come from your body, and I will establish his kingdom. He shall build a house for my name, and I will establish the throne of his kingdom forever. (2 Samuel 7:12–13)

God promises David: one of your great great great great grandsons will be King of the Universe.

This is why Jesus is called the Son of David