How will the millennium end?
The millennium will end through the providential acts of a sovereign God, passing through a time of great turmoil. After that, the new earth and new heaven come on the scene, and their circumstances will be the same as those seen during the thousand-year rule and reign.
Les explains that the thousand-year millennial kingdom will end by the providential acts of a sovereign God, not by human free will or accident. Everything will have to go through a great turmoil. After that turmoil, the new earth and new heaven come on the scene, and the circumstances then will be the same set of circumstances seen during that thousand-year period of rule and reign. Earlier, the context also notes that this kingdom, set up by the God of heaven, shall never be destroyed, and Revelation puts a time element on it: a thousand years, which is called the millennium.