6. many waters--Contrast the "many waters" on which the whore sitteth (Re 17:1). This verse is the hearty response to the stirring call, "Alleluia! Praise our God" (Re 19:4, 5).
      the Lord God omnipotent--Greek, "the Omnipotent."
      reigneth--literally, "reigned": hence reigneth once for all. His reign is a fact already established. Babylon, the harlot, was one great hindrance to His reign being recognized. Her overthrow now clears the way for His advent to reign; therefore, not merely Rome, but the whole of Christendom in so far as it is carnal and compromised Christ for the world, is comprehended in the term "harlot." The beast hardly arises when he at once "goeth into perdition": so that Christ is prophetically considered as already reigning, so soon does His advent follow the judgment on the harlot.

JFB.