The first task relates to the imminent "Rapture of the Church" and how this event shall precede Christ's Second Advent by a period of seven years called the "Tribulation". The term "Rapture" does not appear in the scripture, yet, we know from overwhelming evidence that this "mystery" will occur. Please refer to 1 Corinthians 15:51-52: Paul says "behold, I shew you a mystery; we shall not all sleep, but we shall be changed, in a momment, in the twinkling of an eye, at the last trump, for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed." Further, in 1Thessalonians 4:16-18: "For the Lord Himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God; and the dead in Christ will rise first: then we which are alive and remain shall be caught up with them in the clouds to meet the Lord in the air: and so shall we ever be with the Lord." In the first scripture Paul has declared that we shall all experience death (sleep), but, that we will all be changed from our mortal state, in a momment's notice, so quickly that it is described as "in the twinkling of an eye". We will then be raise incorruptible (no longer slaves to death). Then in Thessalonians 4:16-18 we learn that he will descend to earth with the voice of an archangel. Those "dead in Christ", or, those having accepted Christ as Savior in times past "shall rise first", then those Christians remaining who are alive at this time are "caught up" in the clouds, to meet the Lord in the air to "forever be with the Lord". Notice that the Greek word for "caught up" is Harpazo which actually means to be "snatched away violently". It has been accurately refered to as the Great Snatch.
Here, It is important to acknowledge that we do not know the day and hour of His return. He does not reveal the exact time only when it is "close, even at the door". We do know that we will forever be with the Lord and that we will return to heaven with Christ as He deals with the nations of the world during the tribulation, and, that we are with Him when He returns in triumph and establishes His Millenial Kingdom on Earth. Christians living at the time of the Rapture will escape the terrible time called the tribulation.
Phillipians 3:20-21 states: "For our conversation is in heaven; from hence we also look for the Savior, the Lord Jesus Christ, who will change our vile bodies, that we might be fashioned like unto his Glorious body, according to the working whereby He is able to subdue all things even unto Himself."
The rapture is an event that will occur prior to the tribulation, and, true Christians will be spared the wrath of god which will come upon those living during this time. This does not mean that others will not come to Christ as there will, indeed, be "multitudes" that will accept Christ during this otherwise horrible time. However, they will endure plaques, persecution by the antichrist, as well as the wrath of God on a wayward world. God has prepared a way for His people to accept Him and be spared the "70th Week of Daniel", the tribulation: "Being now justified by His blood, we shall be saved from wrath through Him." Romans 5:9. Also, "For God knows how to deliver the righteous and to reserve the ungodly for the day of judgement." 2 Peter 2:9. And, in Revelation 3:10 "Because thou has kept the Word (Christ) of my patience, I will keep thee from the hour of temptation which will come upon all the world to try them that dwell upon the earth."
In Chapter 21 of Luke, Jesus reiterates what will come to pass during the tribulation in verses 20-37. This passage parallels part of the Olivet discourse in Mathew Chapter 24. Verse 36 reads: "Watch ye therefore, and pray always that ye may be counted worthy to escape all these things that shall come to pass, and to stand before the Son of Man."
Again, He has exhorted us to watch, pray and be prepared that we might escape the tribulation by accepting him now and be caught to Him in the clouds to forever be with the Lord. It is important to realize that the Rapture of the Church occurs prior to the tribulation. The Church is removed from the earth while God deals with the nation of Israel during the tribulation in order to finally convince Israel to accept their true "Messiah" Jesus Christ. Throughout history God has allowed persecution of the Jews because of their rejection of Him as their savior. It may be hard for us to realize how Israel has rejected Christ even as He walked among them; however, it should be no more hard to understand than how so many remain blinded to the truths of His Second Coming in light of world events and God's own Word. Christ said to the Sadducees and the Pharisees in Matthew 16:2-4: "When it is evening you say ‘it will be fair weather today, for the sky is red'; and, in the morning ‘it will be fair weather today because the sky is red and lowering'. O. ye hypocrites, ye discern the face of the sky, but ye cannot discern the signs of the times."