The Tribulation is a period of time, just before the return of Jesus (Matt 24:29-31, Mark 13:24-27, Luke 21:20-28), in which the world will be united by a one world government (Dan 7:7-8, Rev 13) and all people on earth will be tested through the flood of lies (Matt 24:37-41, Luke 17:26-27, Rev 12:15), that comes from the mouth of satan, to see what they will do if their understanding of the truth is put under pressure, and those who do not know God’s Word will be swept away in these lies and this deception. This period of time was originally said to be 7 years, in which antichrist would have been on earth for 3 and a half years (Dan 8:13-14, 9:27, 12:6-10, Rev 11:2, 12:13-14), but Jesus told us that He had it shortened for the sake of His elect (Matt 24:21-22, Mark 13:19-20) because even the elect would be deceived in such a long period of satan running amuck.
(Mar 13:19)For in those days shall be affliction, such as was not from the beginning of the creation which God created unto this time, neither shall be.
(Mar 13:20)And except that the Lord had shortened those days, no flesh should be saved: but for the elect’s sake, whom he hath chosen, he hath shortened the days.
(Mar 13:21)And then if any man shall say to you, Lo, here is Christ; or, lo, he is there; believe him not:
Satan will come to earth as antichrist halfway through this hour of temptation and will deceive the world into believing he is the Messiah, and that he should be worshipped (Dan 8:9-12, 2 Thess 2:3-4). He will be an impostor of Jesus Christ to all Christians, but also he will impersonate the messiah of every other religion, in order to join everyone together in a one world religion (Rev 13:14-15) under the rouse that every religion is basically the same, but misunderstood, and that they all actually have the same messiah.
(Mat 24:26)Wherefore if they shall say unto you, Behold, he is in the desert; go not forth: behold, he is in the secret chambers; believe it not.
(Mat 24:27)For as the lightning cometh out of the east, and shineth even unto the west; so shall also the coming of the Son of man be.
Only those who have studied the Bible, and know Jesus Christ on a personal level, will be able to tell the difference between satan acting as a false Jesus, and Jesus Christ Himself (2Thess 7-12, Rev 13:11). You must study to show yourself approved (2Tim 2:15). This will be a time of great deception like the world has never seen (Matt 24:21, Mark 13:19).
(2Ti 2:15) Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth.