The mystery revealed in 1 Corinthians 15:51 is that not all believers will die; living believers will be changed instantly when Christ intervenes.
Paul calls it a 'mystery' because it had never been revealed before—not in the Old Testament, and not by Jesus. God kept it secret in His mind until He revealed it to the Apostle Paul. The secret is that a group of believers will be alive at the end and will not sleep (die physically); instead, they will be changed.
1 Corinthians 15:51-52 — This is the passage where Paul directly answers the question by calling the truth a mystery and explaining that believers will not all sleep but will all be changed.
In 1 Corinthians 15:51, Paul writes: 'Behold, I shew you a mystery; We shall not all sleep, but we shall all be changed.' The next verse continues: 'In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed.' The words 'we shall not all sleep' show that physical death is not the experience of every believer. There is a group of believers who will be alive when this change takes place, and they will be transformed instantly. In 1 Thessalonians 4:16-17, Paul describes the same event: 'For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first: Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord.'
Les Feldick explains that the word 'mystery' in 1 Corinthians 15:51 means a secret that had never before been revealed. He stresses that God has the right to keep things hidden until He chooses to reveal them, and this truth was kept secret in the mind of God until He revealed it to the Apostle Paul. The secret itself, Les says, is that there will be a group of believers who will not die physically. They will be alive when everything comes to its culmination, and they will be changed. Les points out that the Old Testament never mentioned a group of living people being translated, and Jesus never mentioned it either; it is a Pauline doctrine. He ties this directly to what we call the rapture of the church. Les also teaches why living believers have to be changed: they cannot go to glory in their present bodies. Just as believers who die will be raised with new bodies, living believers must be changed. Paul's words—'we shall not all sleep... but we shall all be changed'—are a secret that has now been revealed, and Les says we are to believe it even if we cannot comprehend it. He also points to 1 Thessalonians 4, where Paul describes the same event even though the word 'mystery' is not used there.
In Paul's day, the inner teachings of pagan religions were called 'mysteries' or secret things. Paul uses the same word, Les notes, to show that this truth had never been revealed. It was not found in the Old Testament, Jesus had never mentioned it, and God had kept it secret in His mind until He revealed it to Paul.
Les is emphatic that the Old Testament never told of a group of living people who would suddenly be gone and translated, and Jesus never mentioned it. This is why Paul calls it a secret. Until Paul, no one had been told that living believers would be changed instead of dying.
According to Les, a living believer cannot go to glory in this old body. Those who have died will be raised to receive a new body, but believers who are alive also need to be transformed. That is why the mystery says 'we shall all be changed.'
Les takes his listeners to 1 Thessalonians 4, where Paul describes the same event even though he does not use the word 'mystery.' Les identifies it as the outcalling or rapture of the church.
God's Hidden Secrets
Les explains that God kept things secret in His mind until He revealed them to the Apostle Paul, showing that a mystery means a secret kept by God.
The Mystery of the Rapture
Les shows Paul calling 1 Corinthians 15:51 a mystery and revealing that one group of believers will not die physically but will be alive when everything comes to a culmination.
A Secret Never Revealed Before
Les emphasizes that Paul is about to reveal a secret that had never been revealed before, and that God has the prerogative to keep things hidden until it is time to reveal them.
We Shall Not All Sleep
Les quotes the secret: 'We shall not all sleep or die physically, but we shall all be changed,' and connects it to 1 Thessalonians 4 as the same rapture truth.
Paul's Revealed Mystery
Les identifies Paul as the one who says 'Behold, I shew you a mystery' in 1 Corinthians 15:51, and says this truth was kept secret in the mind of God until Paul's time.
No Hint in Old Testament or Jesus
Les says nowhere in Scripture before Paul was there a group of living people who would be suddenly translated; Jesus never mentioned it and the Old Testament never mentioned it. Living believers must be changed because they cannot go to glory in their present bodies.
Never Alluded To or Hinted At
Les says what Paul unveils has never been alluded to, hinted at, or spoken before—that at the end of time there will be a group of believers who will not die physically but will all be changed.
A Teaching Found Only in Paul
Les notes that the idea of living people suddenly being translated is found nowhere but Paul, and Paul introduces it in 1 Corinthians 15:51 as another mystery or secret.
1 Corinthians 15:51: Behold, I shew you a mystery; We shall not all sleep, but we shall all be changed,
This is the verse where Paul directly calls the rapture truth a mystery and states that not every believer will die.
1 Corinthians 15:52: In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed.
This verse explains how the change will happen: suddenly, at the last trumpet, when both the dead and the living are transformed.
1 Thessalonians 4:16-17: For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first: Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord.
Paul describes the same event in 1 Thessalonians 4, and Les points to it as the rapture of the church even though the word mystery is not used there.
It means a secret that had never before been revealed. Les says these things were kept hidden in the mind of God until He revealed them to Paul. The truth itself had not been hinted at anywhere in Scripture before Paul.
No. The mystery Paul reveals is that 'we shall not all sleep.' A group of believers will be alive when Christ intervenes, and they will be changed rather than dying physically.
Les acknowledges that Enoch was a good example of an individual being translated, but he explains that Scripture never indicated there would be a group of living people translated until Paul. That group promise was the secret.
Les says no. The Old Testament never mentioned a group of living people being suddenly translated, and Jesus never mentioned it either. It is a Pauline doctrine revealed at 1 Corinthians 15:51.
They are changed. Les teaches that living believers cannot go to glory in their present bodies, so at the event they will be transformed along with the resurrection of the dead.
Watch the Teaching: The Mysteries Paul Revealed — Secrets Hidden Since the World Began