What does Isaiah 27:1 mean?

Commentators are divided about whether this verse stands alone or completes the end of the prior chapter (Isaiah 26:20–21). It is clearly about the Lord's final victory when His judgment of the earth will be followed by His kingdom on earth.

Using symbolism, Isaiah says the Lord will defeat a terrible creature. The name Leviathan is mentioned five times in the Old Testament. One of these credits the Lord with crushing Leviathan's multiple heads (Psalm 74:14). Job chapter 41 depicts a creature which is untamable and monstrous, though this seems to be a different beast than the one Isaiah mentions. Job is meant to understand that God alone created the beast and He alone could control it. Isaiah refers to something related to the end times.

The mystery of this name has fired the imaginations of readers for thousands of years. Ancient Ugaritic and Canaanite mythologies describe a twisting, multi-headed sea serpent. This monster typically symbolizes chaos. Isaiah's words would be a concise way of explaining how God will finally conquer all chaos and evil during the end times.

An alternative interpretation is that this "Leviathan" represents the large nations who opposed Israel and Judah, such as Egypt, Assyria, and Babylon, whose religions included this monster.