The Euphrates is one of the four rivers named as flowing out of Eden, and one of the great rivers of the ancient world. It marked a boundary of the land God promised to Abraham's descendants.
The Euphrates threads through the whole Bible, from the garden of Eden to the visions of Revelation — a reminder of the sweep of God's story across all of history.
The Euphrates in Scripture
And the name of the third river is Hiddekel: that is it which goeth toward the east of Assyria. And the fourth river is Euphrates.