Joel 2:1-3

Blow a trumpet in Zion; sound an alarm on my holy mountain! Let all the inhabitants of the land tremble, for the day of the LORD is coming; it is near, a day of darkness and gloom, a day of clouds and thick darkness! Like blackness there is spread upon the mountains a great and powerful people; their like has never been before, nor will be again after them through the years of all generations. Fire devours before them, and behind them a flame burns. The land is like the garden of Eden before them, but behind them a desolate wilderness, and nothing escapes them.