Joel 2:1-3

Blow the trumpet in Zion; sound the alarm on my holy hill. Let all who live in the land tremble, for the day of the LORD is coming. It is close at hand— a day of darkness and gloom, a day of clouds and blackness. Like dawn spreading across the mountains a large and mighty army comes, such as never was in ancient times nor ever will be in ages to come. Before them fire devours, behind them a flame blazes. Before them the land is like the garden of Eden, behind them, a desert waste— nothing escapes them.