The Great Tribulation is a period of seven years in which God will judge the wicked on the earth. It will be a time of great persecution and suffering for all mankind, and especially for those who remain true to Jesus Christ.
The Bible mentions several different judgments that will occur during the Tribulation. They are referred to as the Seven Trumpet Judgments, the Seven Seal Judgments, and the Seven Bowl Judgments (seven is the number of perfection in the Bible):
Seven Seals:
The Tribulation will begin with the Antichrist rising to power. He will cause the world to believe his words and trust him to bring peace on the earth. Soon, however, his true character will be revealed and the world will break out into complete anarchy and chaos. This will only be intensified as God begins his period of judgment on the earth. Famine and sickness will spread throughout the world, killing millions of people. The Antichrist will begin to persecute believers and powerful earthquakes will strike the earth.
Seven Trumpets:
During these judgments, one-third of the earth will be destroyed with hail, fire and blood. As you can imagine, the earth’s vegetation, animal life, and human life will be greatly devastated. Also, during the Trumpet Judgments, a “mountain” will be cast into the midst of the sea. This is conjectured to mean an asteroid will strike the earth. Whatever the case, it will be an act of God that will send water flooding onto land and killing many. The Bible says that one-third of the earth’s freshwater supply will be as though it is poisoned and the sun, moon and stars will all be dimmed by one-third of their light. A plague of biting locusts will also come upon the earth. This plague will effect the wicked, but not those who have trusted Christ. There will also be a great war that will kill one-third of the earth’s inhabitants.
Bowl (or Vial) Judgments:
Painful sores will break out on all of those who have accepted the “mark of the beast”. The sea will turn to blood, and the sun will burn with an intense heat that has never been felt before on the earth. A world-wide earthquake will level every mountain and great lightnings (meteor showers?) will plague the earth.
As this is occurring, the “armies of the east”, or, all of those who serve and worship the beast, or “Antichrist” will prepare for battle against God.
The attempt of Satan to battle God is futile, rather the Bible says that Satan will be bound and cast into the bottomless pit. Jesus will then make a “New Earth”, set up His Kingdom, and reign with His followers for a thousand years, this is known as the Millennial Reign of Christ.
And he laid hold on the dragon, that old serpent, which is the Devil, and Satan, and bound him a thousand years, And cast him into the bottomless pit, and shut him up, and set a seal upon him, that he should deceive the nations no more, till the thousand years should be fulfilled: and after that he must be loosed a little season. Revelation 20:2-3
What is the Tribulation? Part 1