There will be no more sea!

For example, the disappearance of the sea in Revelation 21:1 (“and the sea was no more”) is not making the point that no one goes swimming in the new creation. Rather, the sea is a traditional symbol in the ancient Near East for the forces of chaos and evil (thus in Rev. 13:1 one of the beasts comes from the sea). The point is that the forces of evil and chaos will be eradicated. Beyond the traditional background of this image, the book of Revelation previously mentioned the exploitative sea trade of the Roman Empire, which will end when Rome, the great city (called, symbolically, “Babylon”), falls (18:11—18); that is why among those who mourn the passing of the city are “all shipmasters and seafarers, sailors and all whose trade is on the sea” (18:17—18). It is therefore good news that in the eschaton the sea (which facilitated the economic expansion of the Roman Empire) will be no more.—J. Richard Middleton, A New Heaven and a New Earth, 169