What is the eschatological verification by John Hick?

The Eschatological Verification is from John Hick's book Faith and Knowledge (1966) which was written as a response to the rise in Logical Positivism. Logical Positivism is the idea that: if something cannot be proven empirically (through scientific observation) then it has no real cognitive meaning. In simple terms, if you can't prove it, then it isn't true. The Logical Positivists were highly critical of Religious belief because they stated that because it isn't proven that God exists, it is pointless and meaningless to say the words "I believe in God".
But John Hick disagreed, and set to work on his "Parable of the Celestial City", providing an alternative explanation as to how Religious belief can be meaningful even without empirical evidence. In Hick's book, he explains (through his parable) that belief in God can only be proven upon reaching the after-life. Within the parable, two men are on a journey trying to find the "Celestial City". One man believes that the path that they walk will reach the city, the other man disagrees and states that they're wandering around aimlessly. Hick's conclusion is that both men will only know if the city is there when they reach the end of the road. This shows how empirical evidence is not required to provide meaning to the statement "I believe in God" because we will only know if God is real upon reaching the after-life. Thus, Hick says that Religious belief is a "genuinely factual assertion" and that the eschatological verification can make Religious belief compatible with Logical Positivism.