See on v. 14. John’s description of the desolate state of ancient Babylon (vs. 21-23) must have been particularly impressive to the people of his day, in view of the fact that it was within their lifetime that the hapless city finally became an uninhabited waste (see on Isa. 13:19).

 Literally, “with a rush,” “with a shock.” This word is used by classical Greek writers of the shock of battle and of a surging flood. In Acts 14:5 a cognate word is rendered “assault.” With one tremendous throw the millstone is hurled into the depths of the sea. Thus, with finality (see on Rev. 18:14), will Babylon sink into oblivion, or “perdition” (ch. 17:8). Compare Jer. 51:42, 64; Eze. 26:3, 19; 27:32, 34.

 Compare Jeremiah’s illustration of the fate of ancient Babylon (Jer. 51:63, 64; see on Isa. 13:19; Rev. 14:8). For a Biblical explanation of the symbol of inundation see Isa. 8:7, 8; Jer. 50:9; 51:27, 42; Eze. 26:3, 4.

A millstone of such a size as was anciently turned by an animal, in contrast with small millstones that were turned by hand.

Literally, “one strong angel.”