2 Thessalonians 2:3 (KJV) 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;
Yet the older translations into English all say “depart”:
2 Thessalonians 2:3 (Tyndale) Let no ma deceave you by eny meanes for the lorde commeth not excepte ther come a departynge fyrst and that that synfnll man be opened ye sonne of perdicion
2 Thessalonians 2:3 (Webster) Let no one deceive you in any way. For it will not be, unless the departure comes first, and the man of sin is revealed, the son of destruction,
2 Thessalonians 2:3 (Geneva) Let no man deceiue you by any meanes: for [that day shall not come,] except there come a departing first, and that that man of sinne be disclosed, [euen] the sonne of perdition,
The word “falling away” and “departure” in Greek is αποστασια and in the Modern Greek language translate as “distance” or “secessionism”. The dictionary says that apostasy means a “defection” which in my opinion would be more apt in this meaning. We as Christians are not part of this world, though we live in this world, and therefore we are defecting from the accepted worldly norm. That is, Jesus aids us in defecting from the earth. The world chooses the devil and we are defecting to God. To put it another way we are abandoning a belief system the world has accepted, of which we were once participants.
Men have since Adam chose to leave the truth for the false, so how is it that this “falling away” can be a sign? In America’s case, we started to depart from the truth in the 1920’s. We’ve come from a clearly born-of-God God-fearing nation to “we do not consider ourselves a Christian nation or a Jewish nation or a Muslim nation. We consider ourselves a nation of citizens who are bound by ideals and a set of values.” President Obama1 He’s correct because even if you count all the “Christians” there are over 41,000 denominations!2 I’m sorry, but the falling away happened long ago.
Here are two articles that explain it better than I can:
http://www.raptureready.com/featured/ice/TheRapturein2Thessalonians2_3.html
http://blogs.blueletterbible.org/blb/2013/01/09/they-shall-not-escape
Remember, the paper copies of the Word of God will remain as a testimony as well as websites. People will be looking for the truth when their governments will be telling lies. In it, they will understand that the rapture was indeed a sign for those left behind to be on the lookout for the Son of Perdition, the Antichrist.
References
1 http://www.huffingtonpost.com/2009/04/06/obama-us-not-a-christian_n_183772.html
2 http://en.wikipedia.org/wiki/List_of_Christian_denominations