The context of this book was that the cult of the emperor, a pagan religion that saw the Emperor of Rome as God, was flourishing, threatening the beleaguered early church, and demanding an inevitable showdown. Through his vision given to him by the Holy Spirit, John sees that his own exile and the martyrdom of Antipas, referred to in 2:13, are but a small foreshadowing of the pain and turmoil that are to come thanks to the power of the state and their opposition to the church. This conflict however is caught up in a much larger conflict, which is that between God and Satan. Even though through Jesus' death on the cross, Satan has already been defeated, there is still significant hardship and suffering that God's people must endure. In such a position, their role is to:
...triumph over [Satan] by the blood of the lamb and the word of their testimony... not lov[ing] their lives so much as to shrink from death. (12:11)
This verse captures the state of Christians both in the context of John's letter and also in the much larger cosmic context, as the victory has already been won through Jesus' resurrection, and so they are able to "triiumph" over Satan, but at the same time the victory has not been won completely yet, so they may need to sacrifice their lives whilst they are waiting for the final victory. The final visions at the end of the book, however, indicate the definite and inevitable nature of that victory and paint a very moving picture of the union of the church with God and the kind of life that eternity in heaven will be. Even though the church is in for a very hard time in the present, they have the ultimate sure hope of eternity with God in heaven to look forward to.