And a mighty angel took up a stone like a groat millstone, and cast it into the sea, saying; add one strong angel (cf. the "mighty voice" in Revelation 18:2; also Revelation 10:1, and elsewhere). The adjective, of course, refers to the mightiness of the deed wrought (cf.
Jeremiah 51:61-64, "Thou shall bind a stone to it, and cast it into the midst of Euphrates; and thou shall say, Thus shall Babylon sink, and shall not rise," etc.). The sea may be typical of the nations of the earth (see Revelation 13:1).
Thus with violence shall that groat city Babylon be thrown down, and shall be found no more at all; Thus with a mighty fall shall Babylon, the great city, be cast down, etc. (Revised Version). Alford translates "with a rush;" ὅρμημα is peculiar to this passage.
The complete nature of this extinction is indicated by the frequency of the words, "no more at all," in Revelation 18:21-23.