Different views place the time of the tribulation at different points in relation to the millennium. In the book of Revelation, the apostle John describes the vast multitude of people who come out of this time of testing and trial.
"These who are clothed with white robes, who are they, and where did they come from?" . . . "They are the ones who have come out of the great tribulation; and they have washed their robes, and have made their robes white in the blood of the Lamb (Revelation 7)
To some teachers of prophecy, the above verses are referring to a specific period called Tribulation. Based on a comparison of relevant prophetic scriptures, many people feel this time of trial will last 7 years. While some reference the entire 7 year period by this designation, others refer only to the last half or three and one half years as being Tribulation. This is done because it is believed the last half of the seven-year period will bring far worse suffering and trial than the first half.
Additionally, many try to figure out WHEN this time of global tribulation, suffering and trials will occur. What is known as Jesus' Olivet prophecies, recorded in Matthew 24, Mark 13, and Luke 21, are used to help determine exactly when the end will come and the Second Coming occurs. When his disciples asked Jesus what would be the signs of his coming to earth during the end time he stated several events. He first warned them to WATCH so that they would not be fooled. Then he said the following.
6. And you shall hear of wars . . . For it is necessary that all these things take place . . . 7. For nation shall rise against nation . . . there shall be famines and pestilences . . . (Matthew 24)
During the great Tribulation, the devil will deceive the entire world into worshipping him in the form of the end time Antichrist (Revelation 13:1 - 4). He will eventually gather all the armies of the world to fight against a returning Jesus Christ (Revelation 16:12, 14).