Thank you my dear friend for your very excellent question. I imagine that the crux of your question has to do with the phrase “…we shall not all sleep…” (die) from 1 Corinthians 15:51, would that be true? You probably are aware that the word “sleep” is the term we use for those who have died on this earth who are believers on the Lord Jesus Christ. There will of course be some who believe when the Lord comes that they will not experience physical or spiritual death because they are saved by Grace through faith. But, in general, because of Adam’s fall, all are subject to physical death (Hebrews 9:27 and Romans 6:23, and many other verses). But we read in 1 Corinthians 15 that when the Lord does come, He will first raise up all believers who have died in faith, and will give each of us, those living and those dead, new bodies, and we will be caught up to meet Him in the air, both the living and the dead who are true Christians (1 Thessalonians 4:16-17). Thus, some believers will not die, but will be alive at the Lord’s coming. Still, all will be changed and caught up to be with the Lord.

So, let me expand on Hebrews 9:27, “And as it is appointed unto men once to die, but after this the judgment…”. In this verse, we see the effects of the curse of the law on every man since Adam, which is death; and if not saved by faith in the finished work of Christ, there will be a judgment after death, culminating in spiritual death. We read in Romans 6:23, “For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord.”  In Ezekiel 18:4 we read that “the soul that sinneth, it shall die.”  Death is the consequence of sin, and death has been going on since Adam.  But for those who have not turned to Christ Jesus as their personal Saviour and Lord, the problem doesn’t stop with physical death. There will be a resurrection to judgment for all the ungodly who have ever lived which occurs after death, and this judgment is that which is being referred to in Hebrews 9:27, and it is described thoroughly in Revelation 20:12-15. Now, what is the outcome of this judgment?  We read in verse 15, “And whosoever was not found written in the book of life was cast into the lake of fire.”  Thus, I believe that those who stand before God at this “Great White Throne” judgment are those who died without seeking God’s mercy and Grace in life. This failure to accept God’s salvation results in the second death. There is no excuse, because salvation through faith and not through works applies to those of all generations, those who lived in the Old Testament days (please read Romans 4:3-5), and also to those in the New Testament times (Acts 4:12; Ephesians 2:8-9). Now, the “second death” described in Revelation 20 is called “hell”, or “the lake of fire”. This is eternal separation from God. But thankfully, there is no condemnation for those who are in Christ Jesus, so the Christian and the Old Testament saint is not subject to this second death. Therefore, I do not believe that God’s saints will appear at this Great White Throne at all. (See Romans 8:1, John 5:24, Romans 6:23, Hebrews 9:28, etc.).

Now, as to 1 Corinthians 15:51, we read, “Behold, I shew you a mystery; We shall not all sleep, but we shall all be changed…”. The Apostle Paul was here responding to some false beliefs among certain of the Corinthian Christians that there was no resurrection, at least not physically (See 1 Corinthians 15:12-21). Now, Paul concludes in verse 22, “For as in Adam all die, even so in Christ shall all be made alive”. Going on, Paul describes how our mortal bodies, those who are in Christ, whether belonging to those who are living or those who have died, will be changed to be made ready for heaven when the Lord returns in verses 50-54, and it is here that I believe your question resides. I will quote a paragraph from the MacDonald Bible Commentary which I believe will help: “We shall not all sleep, that is, not all believers will experience death. Some will be alive when the Lord returns. But whether we have died or are still alive, we shall all be changed. The truth of resurrection itself is not a mystery, since it appears in the OT, but the fact that not all will die and the change of living saints at the Lord’s return is something that had never been known before”.

So, my dear friend, if you are a true believer on the Lord Jesus Christ, you can know with assurance that when the Lord Jesus returns in glory, whether you are living or dead at that time, you will be raised up with a new body, like unto His glorious body (Philippians 3:21). The majority of believers who have lived on this earth will experience physical death due to the fall, and there will be some yet alive when He comes. But all of us who live or have lived who are His true children will be given wonderful new bodies and will be caught up to be with the Lord forever (John 14:1-3). Those who have not believed and die in their sins will be raised up to everlasting judgment as in Revelation 20:12-15.  (SF)  (507.6)