All of Scripture should be read contextually, using good hermeneutical principles in order to do good exegesis. A part of that is recognizing what we are reading. Usually we're pretty good with this, we recognize that the Psalms are different than the Epistles of St. Paul; we recognize that Proverbs and Ecclesiastes isn't the same thing as the Gospels of Matthew, Mark, Luke, and John.
The trouble often happens when we fail to recognize what we are reading when we get to books like the Apocalypse (aka the Revelation) or the book of Daniel.
We're pretty good recognizing poetry, or epistle, or narrative, etc. Those are types of writing which we have a lot of familiarity with. When I read one of Shakespeare's sonnets or plays, I don't get that confused with, say, a biography about Winston Churchill. A book on the history of the American Civil War is a kind of writing I get, and so is poetry by John Milton or T.S. Elliot.
But a form of writing which we are far less familiar with is apocalypse. It's not a literary form that exists in modern times. And when we come across it, as we do in the Bible, we don't necessarily know what to do with it--not without learning about it. Apocalypse, as a form of writing, doesn't really fit into any of the boxes that we are more familiar with: poetry, history, biography, etc. It's a very different kind of writing, one that relies on symbols and loud, graphic imagery to convey meaning--symbols and imagery which very often would have been very familiar for the original target audience, but which be very difficult for us to understand. And that leads us to wildly diverse interpretations. So when it comes to apocalypse, in a lot of ways it's even more important to focus on context, and to not try and take it too literally--because it's not meant to be literal. it's meant to be loud, big, and describe people, places, things, and ideas with highly impactful language: Jesus as a Lamb with lots of eyes; or the devil as a terrifying dragon, Jesus returning in judgment as riding a horse into battle with a sword coming out of His mouth.
That's apocalyptic language. Sometimes, when we are lucky, the authors tell us what some things mean, or maybe just partly. For example, in the book of Daniel we have Daniel as an interpreter of dreams, and so dreams and visions are explained, at least partly. The statue of bronze, iron, etc is plainly described as a series of kingdoms or empires--but doesn't go so far as to identify which. In the Apocalypse of St. John the angel explains to John what the vision of the prostitute riding the beast is, the prostitue--called Babylon--is a city on seven hills (which, I'd argue, is actually a very clear and obvious statement about what city it is, but still many have their own views). Very often, we simply aren't given an answer, or even a hint, as to the meaning of the visions and images: the monsters that come out of the abyss are these monstrous human-faced locusts--what's that about (I have no idea, and I doubt anyone else alive today does either).
So when reading apocalyptic literature, recognize what you are reading. It's not going to fit into any of the boxes that you ordinarily put writing, it's a very special and unique kind of thing, and needs to be recognized as such. That's part of using good exegetical skills to read and understand God's word.
-CryptoLutheran