John had been told to write down what he saw on Patmos and send it to the seven churches, Revelation 1:11. In those churches, John’s words were to be read out loud (Revelation 1:3). Everyone of course has ears, but not everyone actually makes a point of using their ears to really hear what is said. With the words of this verse the hearer whose concentration is drifting or who has set himself in judgment over the words being read is jarred from his reverie or his arrogance and told to listen up and listen carefully. The vision of the teaming up of the beast (fallen humanity) with the dragon is too important to miss!
Similar challenges to the hearers were included in each of the seven letters of Revelation 2:1 – 3:22.
9 If anyone has an ear, let him hear: