Satan's release

“When the thousand years are over, Satan will be released from his prison...” Revelation 20:7
This passage in Revelation puzzled me for a number of years, and also puzzled a number of other believers I know. After a thousand years of Jesus ruling the earth in perfect righteousness, with Satan bound, the earth returned to a pre-Fall state – why would God then allow Satan to be released?
At the second coming of Christ, at the end of the Tribulation, there will be some believers who have survived. They will enter the Millennium still in their physical bodies. At that time we will return to the earth with Jesus, in our resurrection bodies to rule and reign with Him; that is, to enforce His standards of righteousness on the people who will descend from the Tribulation survivors. Since there will be no more curse, sickness, etc. there will be many people born during this period. And here’s the clincher: they will be born into a world where there is no temptation or sin. They will be forced to obey God. They won’t know any different.
After the thousand years, Satan is released for one last task: to give those people the same choice that every person on planet Earth has had since Adam was created: the choice whether to obey God, or to sin. Millions of them will choose to sin – Satan amasses a great force to march against God (Rev. 20:8-9). But like all the others who rebelled against God, they too will be destroyed. After this Satan is thrown into the lake of fire for eternity (Rev. 20:10).
So we can see that even in Satan’s release, God has a purpose and He is in control.