Revelation 21:8 (ESV), “But as for the cowardly, the faithless, the detestable, as for murderers, the sexually immoral, sorcerers, idolaters, and all liars, their portion will be in the lake that burns with fire and sulfur, which is the second death.”
All mankind are not dying as a result of their own sins. All people are under the death sentence due to Adam’s sin. 1 Corinthians 15:22, “As in Adam, all die…” This is mankind’s first death, the Adamic death. Jesus came to earth and took Adam’s punishment of death upon himself. Jesus thus ensured the release of Adam and all of his children from the condition of death. 1 Corinthians 15:22, “As in Adam all die, even so in Christ shall all be made alive.” During Christ’s reign, he will resurrect all mankind (John 5:28,29) and restore all that Adam lost (Acts 3:19-21) when he sinned. People will have their health restored (Isaiah 35:5-10, Job 33:24, 25), their sins will be forgiven and they will learn righteousness (Jeremiah 31:33,34).
However, the scriptures do talk about the possibility of a second death, a death for one’s own sins. This will be a death from which there is no second redemption or second resurrection. Those who die the second death will be completely destroyed in Ghenna, symbolized as the lake of fire and brimstone in Revelation.
In Jesus’ day, Ghenna was the name of the garbage dump outside of Jerusalem. People would throw their trash there and the fire was constantly keep hot in order to consume the refuse. Jesus talked about Ghenna in Matthew 10:28, “And do not fear those who kill the body but cannot kill the soul. But rather fear Him who is able to destroy both soul and body in hell (Ghenna).” Jesus’ point was that God could and will destroy the non-repentant if they refuse to embrace Jesus’ righteous reign on earth. Ghenna pictures second death. Revelation 21:8 references the fire and sulfur of the garbage dump, Ghenna. This pictures the total destruction of that person – both body and soul.
Reading earlier in Revelation 20:14,15, “…death (Adamic death) and hell (hades) delivered up the dead which were in them: and they were judged every man according to their works. And death (the first death or Adamic death) and hell (condition of the first death) were cast into the lake of fire (completely done away with). This is the second death. And whosoever was not found written in the book of life was cast into the lake of fire.”