Revelation 16:13

"And I saw three unclean spirits like frogs come out of the mouth of the dragon, and out of the mouth of the beast, and out of the mouth of the false prophet."

Observe carefully the terms of this verse and see what it proves. What did we have in Chapter s twelve and thirteen? Why, dragon, beast, and lamb-like beast, that is, the beast that had the two horns. What do we have here? The dragon? Yes. The beast? Yes. But what is the last beast called, the beast with the two horns that completes the trio? Here he is called the false prophet. Therefore John identifies that lamb-like beast with the false prophet; and thus we were right in identifying that two-horned beast with the false religion, or Pagan religion of Rome. It is by giving attention to these things that we get the meaning of the Apocalypse.

Verse fourteen tells us that these frogs that came out of the mouths of that trio are the spirits of devils, that they go to the kings of the earth to gather them to the battle of that great day of God Almighty.