I received the following question:

Jeremiah 51 talks about Babylon’s destruction. Is this the day of the Lord time?

Well, that is an interesting question. The majority of the passage seems to speak of the destruction of Babylon that was to come upon it in the near future from the attack of the Medes and Persians. Verse 11 mentions the kings of the Medes, the ones who destroyed it in the past.

11. Make the arrows bright!
Gather the shields!
The LORD has raised up the spirit of the kings of the Medes.
For His plan is against Babylon to destroy it,
Because it is the vengeance of the LORD,
The vengeance for His temple.

Verse 14 seems to describe how the enemy soldiers suddenly appeared in the city of Babylon, as if from nowhere (the watchmen were all drunk and never saw them coming.)

14. The LORD of hosts has sworn by Himself:
“Surely I will fill you with men, as with locusts,
And they shall lift up a shout against you.”

Verse 30 seems to describe how the city fell without even a blow being given in her defense.

30. The mighty men of Babylon have ceased fighting,
They have remained in their strongholds;
Their might has failed,
They became like women;
They have burned her dwelling places,
The bars of her gate are broken.

Verse 31 describes the confusion that prevailed as the Medes took the city.

31. One runner will run to meet another,
And one messenger to meet another,
To show the king of Babylon that his city is taken on all sides;

Verse 32 seems to refer to the blocking up of the river leading under the walls of the city, by which way the enemy entered to open the gates to the rest of their army.

32. The passages are blocked,
The reeds they have burned with fire,
And the men of war are terrified.

Verse 36 seems to refer to the same blocking up of the waters.

36. Therefore thus says the LORD:
“Behold, I will plead your case and take vengeance for you.
I will dry up her sea and make her springs dry.

Verse 39 seems to refer to the fact that the Babylonians were drinking themselves into a stupor when the attack occurred.

39. In their excitement I will prepare their feasts;
I will make them drunk,
That they may rejoice,
And sleep a perpetual sleep
And not awake,” says the LORD.

Verse 57 again seems to refer to the drunken state of the rulers of Babylon when the city fell.

57. “And I will make drunk
Her princes and wise men,
Her governors, her deputies, and her mighty men.
And they shall sleep a perpetual sleep
And not awake,” says the King,
Whose name is the LORD of hosts.

Yet there are a few things that would lead to the conclusion that the future destruction of the city might be referred to here as well. For example, the LORD says they will be desolate forever in verse 26, yet we know that Babylon exists in the kingdom of God, so this may be referring to the future destruction.

26. They shall not take from you a stone for a corner
Nor a stone for a foundation,
But you shall be desolate forever,” says the LORD.

In verses 27-28, this refers to other nations joining the Medes. I guess I don’t know enough about the history of the time to know if this is a reference to the past destruction or not.

27. Set up a banner in the land,
Blow the trumpet among the nations!
Prepare the nations against her,
Call the kingdoms together against her:
Ararat, Minni, and Ashkenaz.
Appoint a general against her;
Cause the horses to come up like the bristling locusts.
28. Prepare against her the nations,
With the kings of the Medes,
Its governors and all its rulers,
All the land of his dominion.

Verse 37 seems more extreme than the past destruction actually was, as well.

37. Babylon shall become a heap,
A dwelling place for jackals,
An astonishment and a hissing,
Without an inhabitant.

So I think it mostly refers to the past destruction of Babylon in the time period of Daniel 4. Yet there could be references here forward to the time of the tribulation, and the great destruction of Babylon that will happen then.