In the first chapter Joel described the plague of locusts that had devastated the land that was supposed to flow with milk and honey; it was the present national crisis before the people of Joel’s day. In this section, Joel is telling the people that they will face a much greater peril than the one that faces them now: The Final Judgment of God.
The first verse calls for the great trumpets to sound the warning, but we mustn’t confuse this with his call for Lamentation in the previous chapter for keep in mind again, he is now talking about the Final Judgment. Since they were facing an actual and literal plague of locusts, the prophet uses locusts here as a metaphor for the judgment; I’m sure you will see this in the verses, for these are obviously not literal insects being described. One clue in the text that tells us this is not a literal passage is the use of the word “like” 9 times to tell us that these “locusts” look or act “like” something other than locusts. Notice also the use of apocalyptic elements that refer to judgment: “darkness, gloom, clouds, blackness, fire, flame” and “desert”.
To ensure that we comprehend that he is referring to the Final Judgment, Joel adds these two verses at the end of our passage:
Before them the earth shakes,
the heavens tremble,
the sun and moon are darkened,
and the stars no longer shine.
The Lord thunders
at the head of his army;
his forces are beyond number,
and mighty is the army that obeys his command.
The day of the Lord is great;
it is dreadful.
Who can endure it? (2:10-11)
These are all apocalyptic elements that, when used in a prophetic context, always refer to the judgment of God, and when this is accompanied by the “day of the Lord” being “great”, they refer to the Final judgment.
Consequently, this passage is a warning that the people must wake up now, for not only are they faced with temporal judgment for their wickedness in the here and now, they face their ultimate doom on Judgment Day. For the original recipients, this is a much more urgent call to repent that it normally would have been because of the simple fact that because of the current crisis, they are facing starvation in the short term and simply cannot put off for a single day responding to Joel’s message. Thus, their preset and literal plague served as both God’s temporal judgment, but His warning of what would come.