It is the judgment of the day of the Lord.
After describing the most fearsome army that has ever existed and will never exist again, Joel says in as many words who is leading this. This is also the worst part: God himself is the general of this army. He leads the way. He is purposefully leading the cruel destroyers to his own people. He is going to punish his children with destruction. He makes no secret of it. With a loud voice he calls upon his army: march, attack, destroy Israel, my own people! They must be severely punished. Each one is attacked, eaten by destructive jaws, burned in the hottest fire. When the army has done its work, there will not even be a skeleton or remnant to be found for burial. The fear of death (Joel 2:2, Joel 2:6) was justified. Nothing and no one can escape God’s judgments. Consider Psalm 130:3. God is furious at his people!
11 L'Eternel fait entendre sa voix devant son armée; Car son camp est immense, Et l'exécuteur de sa parole est puissant; Car le jour de l'Eternel est grand, il est terrible: Qui pourra le soutenir?