The last enemy that will be abolished is death. (1 Corinthians 15:26)
The Bible characterizes death as an enemy. What is death? The late Larry Wright, our dear friend and exceptional Bible teacher said, "Death isn't something... It's the absence of something." As James wrote; For just as the body without the spirit is dead, so also faith without works is dead. (James 2:26)
So physical death is simply the body without the spirit. Spiritual death, however, is the human spirit separated from God. Unbelievers, those who do not know Jesus as their Savior and Lord, may be alive physically, but because of their unforgiven sin, they are dead spiritually; And you were dead in your trespasses and sins.(Ephesians 2:1) While they are physically alive, there is still hope for unbelievers to be resurrected to spiritual life; But God, being rich in mercy, because of His great love with which He loved us, even when we were dead in our transgressions, made us alive together with Christ (by grace you have been saved). (Ephesians 2:4-5)
None of us looks forward to the pain and suffering which often accompanies the physical dying process. But believers have nothing to fear from physical death because nothing, even physical death, can separate us from the spiritual life we have been given in Christ. Unbelievers however, who die in their sins, not only will die physically but will also suffer eternal separation from God in a literal hell. The Bible calls this "the second death"; but for the cowardly and unbelieving and abominable and murderers and immoral persons and sorcerers and idolaters and all liars, their part will be in the lake of fire (eternal hell) that burns with fire and brimstone, which is the second death. (Revelation 21:8)
If the Lord tarries, both believers and unbelievers will experience physical death. However, everyone's body will also ultimately be resurrected, reunited with the human spirit and suited for an eternal existence in either heaven or hell. For us believers, our last enemy, both physical and spiritual death, has been concurred and forever abolished by Christ Jesus our Lord. Maranatha!