Tribulation (Strong's Concordance #G2347) or great tribulations, means distress, misery, affliction and / or persecution. The New Testament sometimes uses this word to denote a period of trial, trouble and testing that will soon come to all man before the arrival of Jesus Christ to rule the world. In the book of Revelation, the apostle John describes the great multitude of people who come out of the Tribulation.
13. And one of the elders answered and said to me, "These who are clothed with white robes, who are they, and where did they come from?" 14. Then I said to him, "Sir, you know." And he said to me, "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 time frame 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 as the (Great) Tribulation, others refer only to the last half or three and one half years as being the 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 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 Jesus was asked by his disciples what would be the signs of his coming to earth during the end time he stated several events.
'Watch out, and do not let anyone fool you. 5 Many men, claiming to speak for me, will come and say, ‘I am the Messiah!’ and they will fool many people. 6 You are going to hear the noise of battles . . . Such things must happen, but they do not mean that the end has come. 7 Countries will fight each other . . . There will be famines and earthquakes everywhere.' (Matthew 24)