Charles Ellicott Commentary Isaiah 27:1

"In that day Jehovah with his hard and great and strong sword will punish leviathan the swift serpent, and leviathan the crooked serpent; and he will slay the monster that is in the sea." — Isaiah 27:1 (ASV)

Leviathan the piercing serpent. —Rather, fleet, or fugitive. The verse paints in vivid symbolic language the judgment of Jehovah on the great world-powers that had shed the blood of His people. The “sword of the Lord” (primarily, perhaps, representing the lightning-flash) is turned in its threefold character as grievous, swift, and strong, against three great empires. These are represented, as in Ezekiel 17:3, Ezekiel 29:3, and Daniel 7:3-7, by monstrous forms of animal life.

The “dragon” is, as in Isaiah 51:19, Psalms 74:13–14, Ezekiel 29:3, and Ezekiel 32:2, the standing emblem of Egypt.

The other two are so generically similar that the “leviathan” (which means “crocodile” in Job 41:1, but here is probably used generically for a monster of the serpent type) serves as a common type for both. While each has its distinctive epithet, they may refer respectively to Assyria and Babylon.

The epithets indicate:

1. the rapid rush of the Tigris and the tortuous windings of the Euphrates; and
2. the policy characteristic of each empire, of which the rivers were regarded as symbols—one rapidly aggressive, the other advancing by sinuous deceit.

By some commentators, however, Egypt is represented in all three clauses, while others (Cheyne) see in them the symbols not of earthly empire, but of rebel powers of evil and darkness, quoting Job 26:12-13 in support of his view.