Jeremiah 30

But they shall serve the Lord their God,
And David their king,
Whom I will raise up for them. v.9

Read chapter 30
So David was Israel's great king of the past, but did you realize that he will be in an exalted governmental position again in the future?  Yes Jesus is the King of kings, but David will be in an exalted position in God's Kingdom (Government).  Bible teacher Nathan C. Johnson describes this verse:

Along with Yahweh their God, the Israelites will serve David their king. How can this be? Is it because the Bible is just calling the Lord Jesus Christ David? This is what some commentators try to do to the passage. Yet I do not believe that this can be true, for David is referred to no differently here than he is in the books of Samuel, Kings, and Chronicles when the historical David is spoken of. Moreover, Yahweh explains how they will serve David their king right in this passage, so there is no need for us to guess. It is not because He is calling Someone else David. It is because He will raise up David for them. Resurrection is the reason David will again be present to reign over Israel under Yahweh their God. Yet many show how little faith they really have in God’s resurrection power when they display an inability to believe this! (Precepts)

During this time of Jeremiah as all of Judah and Israel are or about to go into captivity, he is assuring  them that the Lord won't destroy them completely but will restore them wholly in the Kingdom- even to the point of raising their great godly leader David.  So don't loose heart of never having experienced the godly leader we hear of so often in the Bible or church, we will get to experience him as a leader in God's government soon!
What else do you know of what God's government will be like?  What assurance do you cling to during this time we live in while waiting for the restoring of the world God's going to bring?