> 
> Jeremiah 30:7 (ESV)
> 
> 
> Alas! That day is so great there is none like it; it is a time of
> distress for Jacob; yet he shall be saved out of it.
> 
> 
> 

Based on "there is none like it", my guess is that it is the day of the Lord.

You could say "this is the tribulation" that Jesus was talking but the use of the word "day" tilts my opinion in favor of it being "day of the Lord"