1. Revelation 12:9 (ESV)
  2. Exposition

Why is he also called “the deceiver of the whole world”?

Revelation 12:9 (ESV)

9 And the great dragon was thrown down, that ancient serpent, who is called the devil and Satan, the deceiver of the whole world he was thrown down to the earth, and his angels were thrown down with him.

With his success in Paradise, the serpent deceived not just the single individual Eve (and Adam) but in them all humanity (Romans 5:12). Further, over the centuries the serpent continues to deceive all peoples everywhere. Deception, slander, opposing God remain his mode of operating even today.