Joel 2:1-2

Blow the trumpet in Jerusalem; shout a warning on my holy mountain. Let all the people who live in the land shake with fear, because the LORD’s day of judging is coming; it is near. It will be a dark, gloomy day, cloudy and black. Like the light at sunrise, a great and powerful army will spread over the mountains. There has never been anything like it before, and there will never be anything like it again.