Joel 2:2; Joel 2:31

2 A day of darkness and of gloominess, a day of clouds and of thick darkness, as the morning spread upon the mountains: a great people and a strong; there hath not been ever the like, neither shall be any more after it, even to the years of many generations.

31 The sun shall be turned into darkness, and the moon into blood, before the great and the terrible day of the LORD come.