In I Corinthians 15, Paul is laying out the proof for resurrection from the dead to the Corinthians who said that there was no resurrection. In verse 51 he declares: “Behold, I show you a mystery . . .”
Resurrection from the dead was never a mystery. Even in Job, the first book of scripture to be written, Job says that he will be resurrected. Again in Isaiah, he talks of his dead body being revived. Jesus Christ speaks of resurrection many times. So what is the mystery?
Paul tells us in that same verse: “…we shall not all sleep, but we shall all be changed.” We cannot be a heavenly people if we have an earthly body.