The primary verse everyone uses to describe the Rapture is in 1 Thessalonians:

We tell you this directly from the Lord: We who are still living when the Lord returns will not meet him ahead of those who have died. For the Lord himself will come down from heaven with a commanding shout, with the voice of the archangel, and with the trumpet call of God. First, the Christians who have died will rise from their graves. Then, together with them, we who are still alive and remain on the earth will be caught up in the clouds to meet the Lord in the air. Then we will be with the Lord forever.

- 1 Thessalonians 4:15-17 (NLT)

[emphasis mine]

The phrase "caught up" comes from the word "harpazó" in Greek [Strong's 726]. It literally means, to "seize or snatch up, suddenly and decisively." That is where we get the whole idea of a Rapture. And there is a companion passage of Scripture to this one, again written by Paul that we must also take into consideration.

Now, brethren, concerning the coming of our Lord Jesus Christ and our gathering together to Him, we ask you, not to be soon shaken in mind or troubled, either by spirit or by word or by letter, as if from us, as though the day of Christ had come. Let no one deceive you by any means; for that Day will not come unless the falling away comes first, and the man of sin is revealed, the son of perdition, who opposes and exalts himself above all that is called God or that is worshiped, so that he sits as God in the temple of God, showing himself that he is God.

- 2 Thessalonians 2:1-4 (NKJV) [emphasis mine]

These two passages of Scripture tell us how and when this "catching up" event takes place. Paul gives us a great deal of detail to know exactly what to expect. Thus, all of the following points must be present in order for us to consider the Rapture to be taking place:

  1. The Lord's coming and His gathering together of the Saints happens on the "Day of Christ" (AKA, the "Day of the Lord.")
  2. The Day of the Lord will not happen until there first come a great falling away (apostasy), and the Anti-Christ man of sin is revealed, exalting himself above all by going into the Temple showing himself to be God.
  3. When the Rapture (catching up/gathering) happens, it will be heralded by the Lord's appearing in the clouds accompanied by a shout from the archangel and the sounding of the trumpet of God.
  4. The dead will rise first, then we who are alive and remain will be "caught up" (Raptured) to meet the Lord in the air in bodily form. That means, our physical bodies will literally rise up off the ground and go up into the clouds exactly the way all others in the Bible who were "Raptured" did; Enoch, Elijah and Yeshua all went up in physical form, lifted up from the ground to disappear in the clouds above.

In order for the Rapture to occur, it must happen this way and in no other fashion, for this is how the Holy Spirit revealed the order of events to Paul in the Scriptures.