A fire — The Chaldeans, as a fire shall utterly consume all things. Behind them — What is left behind is as burnt with a flame. As Eden — Fruitful and pleasant.
Related Commentaries of Joel 2:3
Joel 2:3
3 A fire devoureth before them; and behind them a flame burneth: the land is as the garden of Eden before them, and behind them a desolate wilderness; yea, and nothing shall escape them.