“The Day of the Lord is at Hand”

"To the Babylonians the invasion of the Medes and Persians, the destruction of their homes and cities, was 'the day of the Lord.' It was the day of his vengeance and judgment upon them. The prophetic imagery, which here refers to the destruction of Babylon, is applicable to all such catastrophes of historic import. It is, therefore, also descriptive of the last judgment before the Millennium, which is, the fullest meaning of the word, 'the day of the Lord.'" (Reynolds and Sjodahl, Commentary on the Book of Mormon, vol. 1, p. 363)