The army of the Lord returns the shout of the war cry. Hence the battle is enjoined, the result is assured, and the Lord will reign victorious. "The phrase "day of the Lord" first appears in the writings of the eighth-century prophets Amos and Isaiah (Amos 5:18-20; Isa. 2:6-22) to refer to a day of judgment that is so extremely severe that the people will howl with fear." (Ludlow 1982, p. 184.)