New Defender's Study Bible Notes
20:14 cast in to the lake of fire. All who will have been confined in death and Hades will be cast into everlasting fire, along with the devil and his angels (Matthew 25:41), who are already there, and with the beast and the false prophet.
20:14 second death. These will all have died physically, then been resurrected. They will die again physically (or possibly will continue in an eternal state of dying physically—note Mark 9:43–48). This can appropriately be called “the second death.”