This formulation is an echo of God’s own self-characterization in Revelation 1:4, Revelation 1:8, and Revelation 4:8. Yet whereas the Lord God is eternal and unchanging, this beast is finite; it “was” and then went the way of all flesh (“is not”). It cannot, in other words, sustain a link between past and present (let alone future). Jesus died and rose, but his death did not disconnect him from his past or future—for even in death Jesus (true God) did not cease to exist.
8 The beast that you saw was, and is not, and is about to rise from the bottomless pit and go to destruction. And the dwellers on earth whose names have not been written in the book of life from the foundation of the world will marvel to see the beast, because it was and is not and is to come.