The last enemy to be destroyed is death. 1 Corinthians 15:26 (ESV)
In Paul's teaching on the resurrection and restoration of all things, he mentions this important point. That death, being our enemy will be destroyed, as it also says in Revelation 21:4, death shall be no more.
In Christian culture, a spiritual after-life is so accentuated that one hardly notices one of the central truths of the gospel. That Jesus rising from the dead wasn't just to show that Jesus really did pay the bill and you're forgiven, nor was it just about showing that Jesus was telling the truth and is God. More importantly, it was about Jesus overcoming evil and death!
Therefore do not be ashamed of the testimony about our Lord, nor of me his prisoner, but share in suffering for the gospel by the power of God, who saved us and called us to a holy calling, not because of our works but because of his own purpose and grace, which he gave us in Christ Jesus before the ages began, and which now has been manifested through the appearing of our Savior Christ Jesus, who abolished death and brought life and immortality to light through the gospel 2 Timothy 1:8-10
Jesus abolished death, and in it's place brought life and immortality. This immortality is not about some kind of spiritual continuation of our existence in a ghostly or ethereal form, it is distinctly talking about the physical. This is a different Greek word than the one describing God in 1 Timothy 6:16, which is the word "athanasia," which means unable to die. Rather the word used in this passage is "aphtharsia" which denotes incorruptibility, and is referencing a body that does not break down and die. This is what our savior brought and what he saved us from was not eternal conscious torment, but from death.
Since therefore the children share in flesh and blood, he himself likewise partook of the same things, that through death he might destroy the one who has the power of death, that is, the devil, and deliver all those who through fear of death were subject to lifelong slavery. Hebrews 2:15 (ESV)
Jesus overcame death and evil through defeating death for us by taking away the one who has the power of death, which is the devil.
Now the question stands, do Christians still die? Of course they do, now how could this then be referring to Jesus overcoming death for us if we still die? I believe that Conditionalism has the answer for this. It isn't an eternal existence as a spirit, it is a bodily resurrection and salvation from the second death, which is destruction in the lake of fire. God will restore and glorify creation and free it from sin, evil and death forever.
This I believe is central to the gospel, and this teaching is truly brought out with an understanding of Conditionalism as espoused here.
Blessings,
DI