Musterion is the Koine Greek term we have transliterated as “mystery.” In the New Testament it is defined as: “…the secret thoughts, plans, and dispensations of God which are hidden from the human reason, as well as from all other comprehension below the divine level, and hence must be revealed to those for whom they are intended.”
In other words, a “mystery” is revealed divine truth. It could never have been guessed or imagined by sinful humankind. God wants to tell us something incredibly important (Col. 1:26), something we would have never come up with on our own. The apostle Paul uses the word 21 times in the New Testament.
1) For the partial hardening of Israel until the fullness of the Gentiles has come in (Rom. 11:25)—no one would have guessed that God would temporarily lay Israel aside in order to graft Gentiles into the rich olive root of His people.
2) For Jesus Christ Himself! (Col. 2:2)—It was incomprehensible that the infinite and eternal God would become a man, through a virgin, to die for the sins of the world.
Once the sinner believes in Christ, he or she is immediately placed “in Christ” (en Christo) making that person the recipient of unimaginable riches (Col. 1:26) and blessings.
3) In the plural for ”…secret(s) or myster(ies) too profound for human ingenuity”, which were entrusted to the apostles for the benefit of Christ’s church (1 Cor. 4:1).
4) For the creation of a new organism, the Church (Eph.3:3-10)—no one would have thought that God would create a new organism through which to manifest Himself to the world.
5) And for the catching away or Rapture of His Church (1 Cor. 15:51). It is with this last point I would like to offer a few insights.
“Behold, I tell you a mystery; we will not all sleep, but we will all be changed” (1 Cor. 15:51). Let’s consider several aspects of this mystery. We will look at it in the order the inspired text places it: “Behold” (idou)-comes from the imperative form of the word “to see.” Here it means: (you must) “see, look, behold…[it is to arouse] the attention of hearers or readers…by introducing something new”.
One wonders how many believers or their pastor-teachers today are arousing attention to this important biblical mystery. Don’t feel guilty if you are daily looking for His coming! You are obeying your Lord.
“Therefore, be on the alert—for you do not know when the master of the house is coming, whether in the evening, at midnight, or when the rooster crows, or in the morning—in case he should come suddenly and find you asleep. What I say to you I say to all, ‘Be on the alert!’” (Mark 13:35-37).
“I tell you a mystery”—in addition to the above definition John MacArthur adds: “This term refers to truth hidden in the past and revealed in the NT…In this case, the Rapture of the Church was never revealed in the OT.”
“We will not all sleep.” The apostle Paul tells us that believers in Jesus Christ never die, they sleep (koimao—a word from which we get our word “cemetery”). Jesus had earlier used the word this way in John 11:11: “Our friend Lazarus has fallen asleep, but I go, so that I may awaken him out of sleep.” His disciples, being rather spiritually dense at this moment thought He was speaking of literal sleep. To clarify the situation, Jesus simply tells them: “Lazarus is dead” (11:14).
Shortly thereafter, Jesus performs one of the most amazing miracles ever witnessed on this globe. He simply speaks the word and the decaying corpse of Lazarus is instantly changed (undoubtedly “in a twinkle of an eye”), giving us a temporal example of the permanent resurrection yet to come.
“…but we will all be changed.” What does “changed” (allasso) mean? Fortunately, the context provides the answer. In 1 Corinthians 15 we read that the resurrection body will be imperishable (v. 42), glorious (v.43), powerful (v.43), a spiritual body (v. 44), “heavenly” (v. 48) and (made in) the image of the heavenly Man [Jesus Christ] (v. 49)—which confirms what the apostle John also wrote: We will be like Him, because we will see Him just as He is (1 John 3:2).
In regard to this coming “change” of all believer’s bodies the Expositor’s Greek Testament adds the insight that Paul goes on to declare that “the change will be universal, that it will extend to those living when the last trumpet sounds (v. 52), amongst whom he then hoped that many of the present generation would be found.”
I would be remiss if I didn’t add that famous quotation from C. S. Lewis about the nature of the resurrection body:
It is a serious thing to live in a society of possible gods and goddesses, to remember that the dullest most uninteresting person you can talk to may one day be a creature which, if you saw it now, you would be strongly tempted to worship, or else a horror and a corruption such as you now meet, if at all, only in a nightmare. All day long we are, in some degree helping each other to one or the other of these destinations.
It is in the light of these overwhelming possibilities, it is with the awe and the circumspection proper to them, that we should conduct all of our dealings with one another, all friendships, all loves, all play, all politics. There are no ordinary people. You have never talked to a mere mortal. Nations, cultures, arts, civilizations – these are mortal, and their life is to ours as the life of a gnat. But it is immortals whom we joke with, work with, marry, snub, and exploit – immortal horrors or everlasting splendors.”
“…changed, in a moment, in the twinkling of an eye, at the last trumpet…” Who in their right mind would propound that one day there will be a whole generation of people, possibly in the tens or hundreds of millions, who will not physically die, but instead suddenly disappear and be made immortal?
What an outrageous impossibility this would be. Yet this is exactly what Holy Scripture has declared! It has been revealed as a secret from the heart and mind of Almighty God, which makes it a certainty.
“Heaven and earth will pass away, but My words will not pass away” (Luke 21:33).
This change will happen “in the blinking of an eye.” The Greek word “twinkling” (hripe) refers to a very rapid movement…this has traditionally been translated as “twinkling” which implies an exceedingly fast—almost instantaneous—movement of the eyes, but this could be confusing to the modern reader since twinkling in modern English often suggests a faint, flashing light in conjunction with…“of an eye.” “Blinking” is the best English equivalent…although it does not convey the exact speed implicit in the Greek term.”
This lightning fast transformation from mortality to immortality will occur “at the last trumpet.”
In summary, God, through the inspired apostle Paul, commands us to look or pay attention (“behold”) to a long-held divine secret (“mystery”) which no one could have guessed, but God in His perfect timing has now chosen to reveal to His children; that an entire generation (probably numbering in the multi-millions) will not see death (“sleep”) but be instantaneously (“in the blink of an eye”) changed from mortal to immortal, powerful and glorious creatures made in the image of Jesus Christ.
In light of the convergence of multiple biblical last day’s prophecies, it appears that the Rapture of Christ’s church may happen soon.“When you see these things happening, recognize that the Second Coming is near. Truly I say to you, this generation will not pass away until all things take place” (Luke 21:31-32). It is difficult to pinpoint any specific event that would define the last generation in terms of the disasters listed. However, Jesus was talking to Jews in the land of Israel.
Could he perhaps be saying that the generation which sees these things happening will not pass away until all things take place? Psalm 90 defines a generation as lasting 70-80 years (Psalm 90:10). If 1948 is taken as the starting point (of Israel back in the land), then the reader can do the math. And don’t forget to minus the seven-year period of Tribulation.
Although no one knows the day or the hour of Christ’s return for His Church (Matthew 24:36), Jesus enjoins us to know the signs of the times (Matthew 16:3) and the season of his return (Luke 21:29-33).
Brothers and sisters, “straighten up and lift up your heads, because your redemption is drawing near” (Luke 21:28).
 A Greek-English Lexicon of the New Testament and Other Early Christian Literature, Walter Bauer, William F. Arndt and F. Wilbur Gingrich, Frederick W. Danker (BAGD), Second Edition, p. 530.
 Ibid, 530.
 BAGD, 370-371.
 The MacArthur Study Bible, NASB Updated Edition, p. 1726.
 The Expositor’s Greek Testament, W. Robertson Nicoll, Eerdmans, 1979, Vol. 2, p. 941.
 C. S. Lewis, The Weight of Glory And Other Addresses.
 The NET Bible, Biblical Studies Press L.L.C, 1996-2005, p. 2248.