There is a truism in the world of systematic theology regarding the study of human dispensations: human nature fails in every dispensation. In the dispensation of innocence mankind fell, despite the perfection of his sinless nature and the perfection of his environment (forever disproving the socialist theory that if we could only perfect the nature or the social structures of mankind we can create a heaven on earth). In the dispensation of conscience the thoughts of mankind become only evil continually and ended with God judging mankind with a flood (forever showing us the darkness of anarchy). The dispensation of human government led man to idol worship and the judgment of Sodom (showing us that we cannot put our trust in princes). The dispensation of promise ended with captivity in Egypt and the dispensation of law ended with the captivity of Babylon (despite being directly ruled by God Israel turned to idols and sinfulness). And what of the gospel dispensation where we find ourselves now? God showed His love to humanity in shedding His own blood for their sins and where does it lead? It leads to the chapter 13 of Revelation. And now we come to one of the greatest failures of mankind, the dispensation of the kingdom. Before the new world, the new heaven and the new earth, can be appreciated we must see this final failure of the old world. We are presented with a dispensation in which Jesus Christ the Righteous rules this world in perfect righteousness and justice. We are presented with a world in which, unlike Eden, was absent the influence of the devil. And yet it ends with final judgement of mankind for when opportunity first arises they will still rebel against God.
We have entered the 1,000 year reign of Christ upon this earth; the reality of the millennial reign of Christ. This 20th chapter shows us the end of that old world and chapters 21 and 22 show us the glory of the new world.