What does Isaiah 14:6 mean?

Warfare in the ancient Near East was brutal. The kings of the dominant powers of Assyria and Babylon took that brutality to another level. They ruled by fear and intimidation. These kings demanded absolute submission and loyalty from their own people, as well as from conquered kings and nations. Enemies were slaughtered in massive numbers. Headless bodies were sometimes stacked high at the gates of cities as a warning. Children were killed in front of parents. Women who were allowed to survive were raped and impregnated to further humiliate and divide the beaten people. Many survivors were deported to other lands to keep uprisings and rebellion to a minimum. It was a cruel and terrifying time to be alive.

It's no wonder Isaiah reports that at some future date, after the king of Babylon has finally been defeated, the people of Israel will sing this taunt-song about him (Isaiah 14:4–21). They will celebrate the Lord's victory over the king's evil reign. This reign of unrelenting persecution and fury will finally end. The mood calls to mind historical moments, such as the end of World War II when Adolph Hitler was finally defeated. He, too, oppressed the Jewish people nearly to extinction. The celebration at the Jewish peoples return from Babylon over the defeat of Babylon's king will reach similar heights. The Lord will never allow evil to reign forever.