'Second Death' in the Bible

"The person who has an ear should listen to what the Holy Spirit is saying to the churches. The person who has victory [in the Christian life] will not be harmed at all by the second death [i.e., the lake of fire. See 21:8].

The person who shares in this first resurrection is blessed and holy [i.e., for being so dedicated to God]. The second death does not have power over these people, but they will be priests of God and of Christ, and will rule with Him for the thousand years.

Then death and the unseen place of departed spirits were thrown into the lake of fire [i.e., after their spirits were reunited with some kind of a body]. This lake of fire is the second death.

But the place for cowards, and unbelievers, and disgusting people [i.e., because of their terrible sins], and murderers, and sexually immoral people, and sorcerers, and idolaters, and all liars, will be the lake that burns with fire and sulphur. This is the second death."