2 Thessalonians 2

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. vv.3-4

Read chapter 2
So we read again of tribulation times.  We see that before Christ's coming the falling away comes first.  Today we could easily say that many are falling away or have fallen away from God, but that has always been since the fall of man.  So there must be a gathering before a falling away takes place and noted as a sign.  The Greek word for falling away is apostasia, which means revolt yet (some people say means departure and then tries to fit in the rapture).  This passage shows then that the tribulation is not what is to happen next but a great gathering when God speaks and all the world will know and have no doubt God, when God gathers all Israel to be one again and the resurrection into the premillennial Kingdom.  The revolt is not the day of the Lord since that comes as a thief in the night but is a sign that that has to come first.
We read of the antichrist that will set himself as the seat of authority in the temple.
Matthew 24 is Christ's great prophesy of the tribulation before His coming.  The abomination of desolation that Jesus refers to seems to be the antichrist spoken of here that sets himself up as God.  Also, Daniel 9 & 11 mentions of this antichrist taking authority over Israel in the future and that this will last for 3 1/2 years, how long we can guess the tribulation to be.
Oh how we long for the great gathering of God's people and to endure for Christ and not for the antichrist during the tribulation.  Do you believe in the rapture?  Why or what scriptures show that?