Jeremiah 30:9 says, according to the NIV: "Instead they will serve the Lord their God and David their king, whom I will raise up for them."
Most of the other translations are the same.
It seems very clear that it will be David, not one of David's descendants, but how much of a stretch from the original text (Hebrew?) is it to say that Jeremiah is referring to a descendant of David?
The simple answer to your question is that it is not stretching it at all to use the ancestor to refer to the descendent in Hebrew. Often the descendent in Middle Eastern culture identifies with their ancestor by name.
The use of the name David fits within the bounds of Hebrew idiomatic usage as a euphemism. When God speaks of David here, it is a reference to the promise He made.
To understand the verse it is worth looking at the context and origin of the idea presented in it .i.e "David their king, whom I will raise up for them"
It starts back in 2 Samuel 7:8-13
8 “Now therefore, thus you shall say to My servant David, ‘Thus says the LORD of hosts, “I took you from the pasture, from following the sheep, to be ruler over My people Israel. 9 I have been with you wherever you have gone and have cut off all your enemies from before you; and I will make you a great name, like the names of the great men who are on the earth. 10 I will also appoint a place for My people Israel and will plant them, that they may live in their own place and not be disturbed again, nor will the wicked afflict them any more as formerly, 11 even from the day that I commanded judges to be over My people Israel; and I will give you rest from all your enemies. The LORD also declares to you that the LORD will make a house for you. 12 When your days are complete and you lie down with your fathers, I will raise up your descendant after you, who will come forth from you, and I will establish his kingdom. 13 He shall build a house for My name, and I will establish the throne of his kingdom forever.
That is the initial prophesy that Nathan spoke to David shortly after he became king. Almost all of the other passages referring to this prophesy speak of David's descendent.
Biblical hermeneutics teaches us that it is import to in interpret a passage with other like passages and if at all by the same author. Earlier Jeremiah writes about this prophesy but references David's descendent with the term branch.
Jer 23:5 “Behold, the days are coming,” declares the LORD, “When I will raise up for David a righteous Branch; And He will reign as king and act wisely And do justice and righteousness in the land.
This shows that Jeremiah understood the Messiah to be the one to come, not a resurrected David but a descendent of David.
Jesus Christ is the descendant of David, raising a righteous remnant of God's people through His salvation for all nations. 2 Samuel 7:8-13 applies here as does Isaiah 53:1-12 and all of the Messianic promises of the Old Testament. Matthew shows this genealogy in chapter one very well. Israel of course was seeking salvation from kings who would conquer and hold them in exile. The promised savior offered to bear the sins of the people and eternally release the from God's judgment. Isaiah. 53:8-12 unfolds in Luke 23:1-25 and Luke 23:34 at Jesus' trial. In His crucifixion Jesus said to the criminals hanging with Him regarding fear of God's condemnation: "Assuredly, I say to you, today you will be with Me in Paradise." The promise is to all who overcomes that they may eat from the tree of life, which is in the Paradise of God as found in Rev. 2:7.
I believe that the NT twists the prophet's words from the OT. There were many who came after David who were chosen by God from the womb and whom he anointed as king and ruler of all nations. For instance, his son Solomon did what was right in the eyes of the lord but then regressed, and so the lord raised another in his place. Although he built the lord house, it became polluted, so it was destroyed by the Babylonians. King Cyrus was then raised to conquer Babylon, and he initiated the raising of the second temple, which was finished years later but burnt down by the Romans. There is a lot which has been left out from Cyrus to Alexander, whose kingdom was divided up 4 ways after he died. The prophecy of Daniel is key to knowing exactly what was to come for end in great detail. Wisdom and common sense will lead to the truth of who and what the king of all nations is about and is not about. The description of the fourth beast has distinct similarities to someone in the NT. Use wisdom and understand that the sword will be the ultimate weapon to slay all sinners who have not kept God's laws and followed other hods unknown to them because of the deception of the false prophets who lie and write books about their lies. They say "peace" when there is no peace. That fourth beast will destroy all nations because people will worship its power. Ten kingdoms of which one will replace three of them.
Why is it difficult to believe that David will be king again at the millennial reign? He spoke specifically of that great day as he refers to it as the day of Jacobs trouble. Rev 12 details the trouble of isreal as a nation on that great day of ammagedon and how d lord will save them from the dragon. Don't forget that he ascended with all righteous men that lived before Jesus including David and his coming back with same as well as the saints that will be raputred at the sound of the Trump among others. David will be there in person too! So he can't be referring to the descendant of David when David is there raised in person. David will be king in isreal again. There's no ambiguity in that prophesy
