We all suffer the first death–that is, our time on earth ends. The second death in Scriptures refers to the banishment to the lake of fire for those who choose continual rebellion against God during their life.
What is the second death the Bible talks about?
This second death is eternal separation from God. "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" (Revelation 21:8).
Three references in Scripture to the second death all reference the lake of fire. They are found in Revelation. The first, in Revelation 2:11, quotes Jesus as promising that believers will not experience the second death.
Later, Revelation describes a time of Jesus' 1,000-year reign on earth. "Blessed and holy is the one who shares in the first resurrection! Over such the second death has no power, but they will be priests of God and of Christ, and they will reign with him for a thousand years" (Revelation 20:6). Note that those who die as believers during the tribulation will be resurrected, avoid the lake of fire (second death), and reign with Jesus.
Later in Revelation 20, John is told that even death and the grave will eternally suffer the lake of fire, along with those whose names are not in the book of life (Revelation 20:14–15).
It is said that those who are born twice (once physically and once spiritually) will suffer just one death, while those who are born but once (physically) suffer two deaths. We all have a choice—salvation in Jesus, or our own will which is in rebellion to God. Scripture tells of a time of judgement in which those who reject Jesus will suffer and those who accept Him will spend eternity with Him. This is a warning for some, and an encouragement for others to share their faith.
Death - What does the Bible say about it?
What is the relationship between physical death and spiritual death?
Is there really an afterlife?
What happens after death?
How can I be saved?
Truth about Eternity