John, the beloved disciple, while in exile, was given a vision of the seven years of tribulation before the return of Jesus Christ to rule the world with a "Rod of Iron." This vision is both wonderful and terrible, it will be the final battle between good and evil.
In the first chapters, the resurrected Christ is reveled to John, speaking of blessings, warnings, and judgment. Letters to the seven churches in Asia Minor have commendations, condemnations, warnings, and promises, "He that hath an ear, let him hear what the Spirit saith unto the churches."
John is called to heaven and sees God. Escorted by many creatures John is shown the world during the seven year period called The Tribulation. John sees the judgments of God upon this old world in three series of seven judgments each, The Seal Judgments, The Trumpet Judgments, and The Vial Judgments. Each group of Seven becoming more severe.
However, God and Christ are still available to give Salvation "To Who So Ever Will." Through out this book, we are reminded, "For he saith, I have heard thee in a time accepted, and in the day of salvation have I succoured thee: behold, now is the accepted time; behold, now is the day of salvation." (2 Corinthians 6:2 KJV)