In Revelation this image of Daniel’s is picked up and reapplied to a new situation. In chapter 13 John has a vision of a blasphemous beast with seven horns and ten heads that rises out of the sea. As with Daniel’s beasts, this ugly brute was composite, like a leopard with bear’s feet and a lion’s mouth. This sea monster was a symbol for Rome and its emperor, a great political power, granted temporary authority by the dragon (Satan), and in opposition to the church and God. As in Daniel’s vision, this was not a literal monster, but the imagery used by both Daniel and Revelation draws on the longstanding tradition of God’s battle with chaos monsters from the sea.
Perhaps now we can understand a peculiar comment near the end of the book of Revelation to the effect that in the new creation there will be no more sea. We might think of that as a disappointing idea—no more beach holidays, scuba diving, or wind surfing. That is not the point. This is not about water as such. This is about the ever-present danger of chaos and its eventual permanent removal.— The Biblical Cosmos, page 45