What does Revelation 12:15 mean?

Depictions in the book of Revelation are extremely dramatic, often meant to be entirely symbolic. Others seem more literal, or a blend of poetry and plain speech. The serpent's action in this verse might be taken literally or symbolically. It's not entirely impossible that someone might attempt to use flooding as a weapon. It is doubtful, though, that the serpent sent a river of water to sweep escaping Jews away in a flood.

More likely, the flood represents the invading forces of the King of the North—typically identified as Russia. Ezekiel chapter 38 identifies this northern aggressor and predicts it will "go against the land that is restored from war, the land whose people were gathered from many peoples upon the mountains of Israel" (Ezekiel 38:8). Addressing the northern aggressor, the Lord says, "You will advance, coming on like a storm. You will be like a cloud covering the land, you and all your hordes, and many peoples with you" (Ezekiel 38:9). Verse 15 identifies the northern aggressor clearly: "You will come from your place out of the uttermost parts of the north, you and many people with you." The next verse identifies the people targeted by the northern aggressor: "You will come up against my people Israel" (Ezekiel 38:16).