I consider that the Kingdom of God will be established upon the earth when Jesus returns, and consistent with this, it lasts for a long time, a period of peace and righteousness and equity. This period is alluded to in a correct reading of 1 Corinthians 15 and necessitated by such passages as Isaiah 2:1-4, Daniel 2:44 and Zechariah 14. Revelation 20 is consistent with all of this, speaking of the return of Jesus, the reward of the faithful, their ruling with Jesus as kings and priests. The only detail that is new and not difficult to accept, is that this period of time will last 1000 years. We must be careful and attempt to understand and distinguish what is literal and what is symbolic.