According to this verse whoever participates in the first resurrection is blessed and holy. “Blessed” is a beatitude that means “happy” or “spiritually prosperous.” A blessed person may not be materially rich, but he is happy and spiritually prosperous. All who rise from the dead in the first resurrection, regardless of when or how they died, are blessed, and they are free forever from the second death. The second death refers to suffering forever in the lake of fire (Revelation 20:14).
Participants in the first resurrection will perform priestly and kingly duties during the thousand-year reign of Christ. The designation, “thousand years,” occurs six times in chapter 20, so it would be hard to reject this designation as something other than a literal period of time. Prior to the thousand years, Christ returns to earth and destroys the armies that oppose Him. He throws the Beast and the False Prophet into the lake of fire. Also, before the thousand years begin, an angel incarcerates Satan in the bottomless pit, tribulation martyrs are resurrected, and thrones of judgment are established (Revelation 20:1–4).
Revelation chapter 20 represents the final lesson, final judgment, and final victory of the end times. Satan is bound, but not destroyed, and released after a thousand years of peace and righteousness. Proving that no evidence or reason to believe in and follow Jesus is enough for those determined to rebel, some follow Satan and are destroyed in a rebellion. Those who died without faith in Christ, through all of history, are resurrected to face the great white throne judgment. There, they are sentenced for sin and consigned eternally to the lake of fire.
Revelation 20:4–10 focuses on the reign of Christ during the millennium: the thousand years of Christ’s rule on earth, as well as what happens at the end of that era. The millennial reign begins after the Devil is imprisoned in the bottomless pit (Revelation 20:1–3) and before the unrighteous dead of all periods of history are judged and consigned to the lake of fire (Revelation 20:11–15). These events precede the descent of the New Jerusalem from heaven (Revelation 21).