Joel 2:1-2

Blow the trumpet in Zion; sound the alarm signal on my holy mountain! Let all the inhabitants of the land shake with fear, for the day of the LORD is about to come. Indeed, it is near! It will be a day of dreadful darkness, a day of foreboding storm clouds, like blackness spread over the mountains. It is a huge and powerful army – there has never been anything like it ever before, and there will not be anything like it for many generations to come!