You will not find the expression “day of the Lord” in the Old Testament prior to the books of the prophets. Joel turns the phrase more frequently than anyone else, but Isaiah also uses it, as do Jeremiah, Ezekiel, Amos, Obadiah, Zephaniah, Malachi and, of course, the prophet we are currently studying, where it appears exactly once, introducing the final chapter.
Naturally, that’s not all the Bible has to say about the day of the Lord. Not by a long shot.