“Now we beseech you, brethren, by the  coming of our Lord Jesus Christ, and by our gathering together unto him,  that ye be not soon shaken in mind, or be troubled, neither by spirit,  nor by word, nor by letter as from us, as that the day of Christ is at  hand. Let no man deceive you by any means: for that day shall not come,  except there come a falling away first, and that man of sin be revealed,  the son of perdition; Who opposeth and exalteth himself above all that  is called God, or that is worshipped; so that he as God sitteth in the  temple of God, shewing himself that he is God.” – Thessalonians 2:1-4 2 Thessalonians 2 is a passage in the Bible that warns us not to be  deceived about the second coming of Christ. I have often used this  passage to show people the truth about when the rapture will take place,  but lately I have been shocked at the response that some people have  given me. Apparently, those who believe that the rapture takes place  before the tribulation actually believe that the “falling away”  mentioned in verse 3 is referring to the rapture!
First of all, 
things don’t fall up! How can anyone actually believe that the “
falling away” is referring to believers being “caught 
up together” in the clouds?! Not only that, but the Bible uses the term “falling away” in other places, and the meaning is clear:
“They on the rock are they, which,  when they hear, receive the word with joy; and these have no root, which  for a while believe, and in time of temptation fall away.” – Luke 8:13 Is this a passage on the rapture? No, it is clearly referring to people  falling away spiritually, which is a bad thing. This may seem basic, but  when something falls it goes 
down, not up.
“For it is impossible for those who  were once enlightened, and have tasted of the heavenly gift, and were  made partakers of the Holy Ghost, And have tasted the good word of God,  and the powers of the world to come, If they shall fall away,  to renew them again unto repentance; seeing they crucify to themselves  the Son of God afresh, and put him to an open shame.” – Hebrews 6:4-6 Again, this passage is definitely not referring to the rapture. This is talking about people falling away spiritually.
In an article entitled “Left Behind at the Rapture,” David Stewart of the website “Jesus is Savior dot com” writes:
“The word ‘rapture’ is not found in  the Bible, but the phrase ‘falling away’ certainly is.  Though some  theologians have concluded that the ‘falling away’ is only referring to  ANARCHY, this erroneous teaching does not harmonize with the rest of the  Bible.  ‘Falling away’ in 2nd Thessalonians 2:3 in the Greek simply  means ‘a departure.’” – David Stewart
Here is an excerpt from his article “The Pre-tribulation Rapture:”
“I also believe that the word  ‘Rapture’ does NO injustice to the Scriptures. The word ‘Rapture’ means  ‘to be caught away.’ In the following Scriptures (2 Thessalonians  2:1-4), we read the term ‘a falling away.’   “The Greek meaning for this phrase is ‘a departure.’ I believe this that this term refers to the departure of the Saints.” – David Stewart
Since things don’t fall up, David Stewart has decided to “go back to the  Greek” to tell us what the Bible REALLY says. Since I believe that the  King James Bible is the preserved word of God, I don’t think it is  necessary at all to “go back to the Greek” since the term “falling away”  is used repeatedly in our English Bible, and it is very clear what it  means.
Mr. Stewart here deceitfully uses the Greek as a justification for  changing what the Bible says. He claims that the Greek word simply means  “a departure.” What he fails to mention is that the Greek word here is  “αποστασια” or in Latin letters “apostasia.” If he had mentioned that,  it may have been a little too obvious that the Bible is referring here  to apostasy, i.e. falling away from the faith, 
not the rapture! The “departure” being referred to is a departure from the faith which is exactly what “apostasy” is!
“Now the Spirit speaketh expressly, that in the latter times some shall 
depart from the faith, giving heed to seducing spirits, and doctrines of devils;” – 1 Timothy 4:1
The Greek word “apostasia” is used in only one other verse in the Bible:
“And they are informed of thee, that thou teachest all the Jews which are among the Gentiles to 
forsake Moses, saying that they ought not to circumcise their children, neither to walk after the customs.” – Acts 21:21
"Forsake" is the English translation of the Greek word "apostasia."  Again, this is a forsaking of doctrine, which is the definition of  “apostasy.” This deception illustrates why you should always take  everything you hear with a grain of salt when preachers are “going back  to the Greek.” Usually they are just trying to change what the Bible  says, as is the case here with a “
falling away” being twisted into being “caught 
up” to the clouds.
Now that we have seen how the Bible itself defines “falling away” (departing from the faith), look at the passage again:
“Now we beseech you, brethren, by the coming of our Lord Jesus Christ,  and by our gathering together unto him, that ye be not soon shaken in  mind, or be troubled, neither by spirit, nor by word, nor by letter as  from us, as that the day of Christ is at hand. Let no man deceive you by  any means: for that day shall not come, except there come a falling  away first, and that man of sin be revealed, the son of perdition; Who  opposeth and exalteth himself above all that is called God, or that is  worshipped; so that he as God sitteth in the temple of God, shewing  himself that he is God.” – Thessalonians 2:1-4
The passage clearly states that the Day of Christ is not at hand, and  that we should not allow people to deceive us that it is at hand. It  goes on to say that the Day of Christ shall not come until AFTER there  is a falling away, and AFTER the man of sin (antichrist) is revealed by  sitting in the temple of God and claiming to be God. This event is  referred to in the Bible as the Abomination of Desolation (see Daniel  11, 12 and Matthew 24).
Anyone who tells you that the Day of Christ is at hand is deceiving you  according to the Bible. What is the Day of Christ? The "Day of Christ"  is referred to 7 times in the Bible:
1 Cor 1:8  Who shall also confirm you unto the end, that ye may be blameless in the day of our Lord Jesus Christ.
1 Cor 5:5  To deliver such an one unto Satan for the destruction of the  flesh, that the spirit may be saved in the day of the Lord Jesus.
2 Cor 1:14  As also ye have acknowledged us in part, that we are your  rejoicing, even as ye also are ours in the day of the Lord Jesus.
Phil 1:6  Being confident of this very thing, that he which hath begun a  good work in you will perform it until the day of Jesus Christ:
The rapture cannot occur until the day  of Christ since that is when the good work of sanctification he began in  us will be complete, and we shall be like him, for we shall see him as  he is.Phil 1:10  That ye may approve things that are excellent; that ye may be sincere and without offence till the day of Christ;
Phil 2:16  Holding forth the word of life; that I may rejoice in the day  of Christ, that I have not run in vain, neither laboured in vain.
2 Thess 2:2  That ye be not soon shaken in mind, or be troubled, neither  by spirit, nor by word, nor by letter as from us, as that the day of  Christ is at hand.
The Bible is very clear that the rapture takes place 
AFTER the tribulation:
Matt 24:29  Immediately 
AFTER  the tribulation of those days shall the sun be darkened, and the moon  shall not give her light, and the stars shall fall from heaven, and the  powers of the heavens shall be shaken:
Matt 24:30  And then shall appear the sign of the Son of man in heaven:  and then shall all the tribes of the earth mourn, and they shall see the  Son of man coming in the clouds of heaven with power and great glory.
Matt 24:31  And he shall send his angels with a great sound of a  trumpet, and they shall gather together his elect from the four winds,  from one end of heaven to the other.