D. A. Carson and Douglas J. Moo, An Introduction to the New Testament (2d ed.; Grand Rapids: Zondervan, 2005), pp. 721–22 (bold emphasis added):

If, as we have argued, Revelation focuses on the end of history, then it is in the area of eschatology that it makes its most important contribution. Nowhere are we given a more detailed description of the events of the end; and while many interpreters have been guilty of finding far more specifics in John’s visions than his symbolism allows and of unwisely insisting that only their own circumstances fit those specifics, we should not go to the other extreme and ignore those details that John does make relatively clear.

But it is shortsighted to think of eschatology simply in the sense of what will happen in the end times. For the End, in biblical thought, shapes and informs the past and the present. Knowing how history ends helps us understand how we are to fit into it now. Particularly  is this so because the New Testament makes it clear that even now we are in “the last days.” Thus, Revelation reminds us of the reality and severity of evil, and of the demonic forces that are active in history. . . . At the same time, the degree to which Revelation exhorts believers should not be neglected. . . .

John’s visions also place in clear relief the reality of God’s judgment. A day will come when his wrath will be poured out, when sins will have to be accounted for, when the fate of every individual will depend on whether or not his or her name is “written in the Lamb’s book of life.” Equally clear, of course, is the reward that God has in store for those who “keep the word of endurance” and resolutely stand against the devil and his earthly minions, even at the cost of life itself. John’s visions are a source of comfort for suffering and persecuted believers in all ages.