Prepare yourself for a shock, I'm about to say something revolutionary: The Bible is a rather large book. Ok, evidently no one is surprised by that. But what does surprise me is that there are people who treat it as if it isn't a book. Or at least as if it isn't a normal book. I've seen people treat it as notebooks for them to include their own personal opinions, as treasure books so they can "read between the lines" to find meanings that just aren't there, a sacred book that the common man has no right to touch, or even as a decorative book for people who want their library to look nice.
But the fact remains that the Bible is a book. Just like a book, there are several rules to interpretation. These rules, called the rules of hermeneutics, are:
- The Bible must be interpreted literally
- The Bible must be interpreted historically
- The Bible must be interpreted grammatically
- The Bible must be interpreted contextually
- The Bible must be interpreted in light of itself
Literally
The word "literally" is often misunderstood. It is typically taken to mean without "figures of speech or descriptive language", but this is not what we actually mean. Few documents, particularly those of antiquity, are written with such wooden literalism. Rather, interpreting the Bible literally means "in its plainest sense". Trees do not literally clap their hands (Isaiah 55:12), nor are there actual bars that hold off the sea (Job 38:8). These are figures of speech, not intended to be taken literally, though they do convey a literal truth. Typically, however, the Bible reads like any other historical text. The plainest sense of a word or sentence should be taken by default, unless context suggests otherwise. The days in Genesis are the most obvious example, as this is the one time when even Christians will arbitrarily seek alternative, allegorical interpretations. Yet, the default meaning of the word "day" is, indeed, day. Not only does the context not prompt us to take alternative interpretations, but actually prevents us. There was evening, there was morning, the X day.
Historically
It shouldn't need to be said, but a first century Jew would read the Bible very differently to a 21st century Brit. Various things in the Bible have little meaning today unless we bring the meaning they had back then into the modern day. Take, for example, "...all they that take the sword shall perish with the sword." (Matthew 26:52b). No one carries swords anymore, but back then, they were an easily recognisable symbol of both authority and judgement. If you attacked the Roman army, as Peter did in defence of Jesus, you were almost certainly going to be executed. Today, the same principle applies, but the weapons of resistance are different. The principle is that peace is preferable to violence. Even a government as evil as the Romans had legitimate (and, more to the point of this verse, visible) authority. Today, we too have governments, and to oppose them will likely result in some form of judgement, even lacking capital punishment.
Grammatically
Just as a lot of historical context is different now, so is linguistic context. Although translations are more than sufficient to convey all essential doctrines, an understanding of the original language really helps. For example, you may notice that in Genesis 1, God says "let us" a lot. That is not because there are multiple gods. Rather, it is because the Hebrew word "Elohim" is plural (likely an early reference to the Trinity).
Contextually
There are two types of context: Historical and immediate. The first part covers the second rule. You interpret each verse according to its historical background. But just as important is that each verse must be interpreted according to the surrounding verses as well. As an example, take Luke 19:27. In this verse, which some Bibles have in red letters to note this is Jesus speaking, we read "But bring here those enemies of mine, who did not want me to reign over them, and slay them before me.’" Christianity is a notoriously peaceful faith, so such words from Jesus seem majorly out of character. Did Jesus really tell His followers to kill His enemies before Him just for refusing to follow Him? Sam Harris says yes. Luke 19:11-26, however, say no. This is because Jesus is quoting a newly appointed king in a parable He was telling. It is not a command to Christians, but a figurative portrayal of the future judgement that both Christians and the world will receive when He comes back.
According to itself
Arguably the most important rule of hermeneutics is that scripture interprets scripture. While an atheist might go out of his way to "prove" the Bible has contradictions, Christians ought to be aware that it was all breathed out by the same non-contradictory God, and thus it will all teach the same message. The surrounding verses are not always the only relevant verses. As an example, let us take the account of Legion. Three of the four Gospels describe this event. Matthew 8:28-34, Mark 5:1-20, and Luke 8:26-39 all tell the story, but what's unique about Matthew's Gospel is that he says there were two demon possessed men, whereas Mark and Luke only focus on one. Taking only Mark and Luke's accounts, one might imagine there was only one demoniac, but Matthew's Gospel demands we acknowledge that in both Mark and Luke, a second demoniac is present, but is not mentioned.
Unfortunately, mankind will always be error prone. We can read the Bible incorrectly. However, our chances of doing so are significantly reduced if we do not add to, or remove from these simple rules. Basically, just read the Bible like any other book and you're highly likely to draw the correct conclusion. Fail to do so, you're all but guaranteed to run into some form of egregious error.