MeanMrMustard
Just read it grammatically. Just because Jerimiah was speaking to the Jews doesn't change the meaning of words.
Babylon was going to reign for a while. Judah was going to "serve" the king of Babylon, along with the other nations round about, for 70 years. It was highly encouraged that Judah accept this servitude. They didn't. So it got worse, in 587, a couple decades into the "servitude", with the final deportation and destruction of Jerusalem. The captives went off into exile to "fulfill" (Chronicles and Daniel) or complete the rest of the time.
Then as v12 says, when the 70 years ended, Babylon was punished/removed from power. But the order in v12 matters.
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Grammar won't help you. You need to read this passage contextually and with the rules of exegesis by means of observation to understand what Jeremiah is saying:
'And all this land will be reduced to ruins and will become an object of horror, and these nations will have to serve the king of Babylon for 70 years". - Jer. 25:11, NWT, 2013 .
You will notice that there are four elements in this verse:
1. Land (Judah) to be desolate
2. Land to become an object of horror
3. Nations to serve Babylon
4. Period of 70 years
All of these elements are tied together in a single verse which concludes the pericope beginning from verse 8. thus the immediate context is from vss 8-11 which beginning from vs. 1 indicates that this prophecy was received by Jeremiah in the 4th year of King Jehoiakim.
Notice that in vs.9 that Jeremiah combines Judah with the nations in terms of this future judgment throughout and concludes and identifies the period of judgement as a period of 70 years as in vs. 11.
This pericope concluding with vs. 11 shows that Judah would become desolate and serve Babylon for 70 years and that the nations also would serve Babylon for that same period of 70 years.
What can we learn from this verse?
WE learn that the 70 years was a fixed pr-determined historic period having a definite beginning and end with no fuzzy terminuses such as 539 BCE- Fall of Babylon; 605 BCE- Neb's acc yr; 609 BCE - Fall of Assyria
WE learn that the 70 years was a period of time during which the Land was desolate and thus empty of its inhabitants having been deported to Babylon as Exiles.
WE learn that this period of Exile was also a period of servitude to Babylon or a period of Babylonian domination over Judah and the surrounding nations.
WE learn that the 70 years as a composite historic period had a precise beginning and end namely the Fall of Jerusalem in 607 BCE and the Return of the Jews in 537 BCE
WE learn that this composite period was of three elements; DESOLATION-EXILE-SERVITUDE.
scholar JW