Behold! I tell you a mystery. We shall not all sleep, but we shall all be changed, in a moment, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, and the dead will be raised imperishable, and we shall be changed.  (1 Corinthians 15:51-52 ESV)

Many of the believers in Corinth struggled to understand what death held for them.  Paul calls the journey to the afterlife a mystery, and it can only be so.  But he does not mean they were left clueless, because the prophets and apostles were given revelation, and this is what he means by a mystery, that which is revealed by the Spirit of God through the Word of God.

Paul says this, that on death there is no waiting, no limbo or Hades (in the Hebrew, Sheol) but an instantaneous resurrection.  The phrase he uses that is translated ‘twinkling of an eye’ is ῥιπή ὀφθαλμοῦ rhipe opthalmou, a rapid movement of the eye; this is blink or wink in more standard English.  A twinkle, as used is in the phrase twinkling stars, is something that happens in the briefest moment of time.  And so it is at death.  There is no long journey.  Jesus says this to the man dying next to him on the cross, who professes the Jesus is the King of Heaven:

‘Truly, I say to you, today you will be with me in Paradise.’  (Luke 23:43)

‘Today’ translates the adverb σήμερον semeron and it means ‘this day’ but also ‘now’, ‘this very moment’.

The church that Paul found in Thessaloniki also struggled with understanding life after death, but their concern was with the Rapture and whether it would confer preferential rights over those that of the faith that died.

 But we do not want you to be uninformed, brothers, about those who are asleep, that you may not grieve as others do who have no hope. For since we believe that Jesus died and rose again, even so, through Jesus, God will bring with him those who have fallen asleep. For this we declare to you by a word from the Lord, that we who are alive, who are left until the coming of the Lord, will not precede those who have fallen asleep.  (1 Thessalonians 4:13-15)

This of course is entirely consistent with the instantaneous change at death to immortality.

The problem is not limited to the early Greek churches, human minds can only grasp temporality.  Time’s arrow flies one in direction, from past through the present to the future.  There is cause and effect; events have to happen in an order, one after the other.

But eternal life is not so constrained.  

‘I am the Alpha and the Omega,’ says the Lord God, ‘who is and who was and who is to come, the Almighty.’  (Revelation 1:8)

In the eternal, God exists across all time – as does everyone, eternally speaking.  In eternity, there is no before and after:

 For those whom he foreknew he also predestined to be conformed to the image of his Son, in order that he might be the firstborn among many brothers.  (Romans 8:29)

If time does not place things in order, then all moments exist in simultaneity.  For example, when in death a wife precedes her husband, the husband mourns her loss, but from the wife’s perspective they are already together, because even if fifty years should elapse, their resurrection to eternal life is instant and simultaneous.

It should also be noted that all Scripture, including the Tanakh (Old Testament) attests to humanity being resurrected:

‘…And many of those who sleep in the dust of the earth shall awake, some to everlasting life, and some to shame and everlasting contempt. And those who are wise shall shine like the brightness of the sky above; and those who turn many to righteousness, like the stars for ever and ever. But you, Daniel, shut up the words and seal the book, until the time of the end. Many shall run to and fro, and knowledge shall increase.’  (Daniel 12:2-4)

Daniel has foreknowledge of the mystery, some of which, the outcome of judgment on all humanity, is sealed.  Jesus affirms himself as the judge:

For as the Father has life in himself, so he has granted the Son also to have life in himself. And he has given him authority to execute judgement, because he is the Son of Man.  Do not marvel at this, for an hour is coming when all who are in the tombs will hear his voiceand come out, those who have done good to the resurrection of life, and those who have done evil to the resurrection of judgement. (John 5:26-29)

In his vision, John sees more the first resurrection to life: 

Blessed and holy is the one who shares in the first resurrection! Over such the second death has no power…(Revelation 20:6)

Those that die in belief are immediately raised and are not subject to the White Throne Judgment where the books of life are opened.

Then I saw a great white throne and him who was seated on it. From his presence earth and sky fled away, and no place was found for them. And I saw the dead, great and small, standing before the throne, and books were opened. Then another book was opened, which is the book of life.  (ibid 20:11:12)

Here is the second resurrection to (the second) death:

And the dead were judged by what was written in the books, according to what they had done.  And the sea gave up the dead who were in it, Death and Hades gave up the dead who were in them, and they were judged, each one of them, according to what they had done. Then Death and Hades were thrown into the lake of fire. This is the second death, the lake of fire. And if anyone’s name was not found written in the book of life, he was thrown into the lake of fire.  (ibid 20:13-15)

All this happens instantly for both those that die in faith and those that do not.  And none escape an assessment of their deeds.  

Having explored the futility of mortal gain, Solomon concludes:

Fear God and keep his commandments, for this is the whole duty of man. For God will bring every deed into judgement, with every secret thing, whether good or evil.  (Ecclesiastes 12:13-14)

For the those of the first resurrection to life eternal:

Let each one take care how he builds upon it. For no one can lay a foundation other than that which is laid, which is Jesus Christ.  Now if anyone builds on the foundation with gold, silver, precious stones, wood, hay, straw— each one’s work will become manifest, for the Day will disclose it, because it will be revealed by fire, and the fire will test what sort of work each one has done. If the work that anyone has built on the foundation survives, he will receive a reward. If anyone’s work is burned up, he will suffer loss, though he himself will be saved, but only as through fire. (1 Corinthians 3:10-15)

This is sometimes called the bema judgment, or ‘the Judgment Seat of Christ’, which is the believer’s judgment.  Thus, for all in eternal kingdom of God, there is a difference for those that undertook Godly work and loss for those who declined to do so.  This is not a matter of salvation but reward.

What is clear from Scripture that eternal life is corporeal, that is in the body, thus physical not ethereal and all we dwell in an eternal city with feet on the ground.  There is no reason at all to treat John’s revelation as merely symbolic or metaphorical, even if he did struggle to translate eternal reality in language and concepts the limited mind can digest.

Then the angel showed me the river of the water of life, bright as crystal, flowing from the throne of God and of the Lambthrough the middle of the street of the city; also, on either side of the river, the tree of life with its twelve kinds of fruit, yielding its fruit each month. The leaves of the tree were for the healing of the nations. No longer will there be anything accursed, but the throne of God and of the Lamb will be in it, and his servants will worship him. They will see his face, and his name will be on their foreheads. And night will be no more. They will need no light of lamp or sun, for the Lord God will be their light, and they will reign for ever and ever. (Revelation 22:1-5)

And John was shown what was sealed to Daniel, so that the Spirit of God, through faith, can reveal the truth:

John’s heavenly guide says this:

‘These words are trustworthy and true. And the Lord, the God of the spirits of the prophets, has sent his angel to show his servants what must soon take place.’ (ibid 22:6)

‘Soon’ translates ἐν τάχει en tachei ‘in haste’ from taxos which means a brief moment of time.  Those saved through faith in Jesus as Lord do not wait even an instant to be with him in place where: 

He will wipe away every tear from their eyes, and death shall be no more, neither shall there be mourning, nor crying, nor pain any more, for the former things have passed away.  (Revelation 21:4)