In any discussion about any religious text (or indeed about any written work), context is absolutely essential. Lacking correct context will inevitably lead to mistakes.
The example I most often like to use is Luke 19:27, which says "But bring here those enemies of mine, who did not want me to reign over them, and slay them before me.’" This verse, taken out of context, sounds horrible, and when we consider that it is Jesus speaking (note that we've already added a little bit of context), it makes Christianity sound like a violent religion. Indeed, this is how Sam Harris intended his audience to understand this verse.
But then you back up a few verses and you see that actually, when you start at Luke 19:11, Jesus isn't commanding His earthly followers to kill anyone, neither was anyone killed following this verse. In fact, to my knowledge, no Christian has ever killed anyone because of this verse. But even if they had, the context of the verse shows that they would have interpreted it wrong.
In reality, Jesus was telling a parable of a king who went away, then when he came back, he executed some rebels for treason. Thus, the absolute best anyone can ever say is that the parable describes how Jesus is going to judge the world when He comes back, commanding His angels to kill His enemies. In other words, far from showing Christianity is violent, this verse indicates that Christianity is going to be peaceful until Christ comes back.
And so we see that context matters. Merely reading a Bible verse can often lead to an incorrect understanding of it. This is great for the heretic who wants to defend a bad doctrine, or an unbeliever who really wants to "prove" the Bible wrong. They can make it support their false doctrines, or make it sound wrong, just by making it seem to say something it absolutely doesn't say. But for the Christian, and indeed any honest person regardless of their personal faith, it is essential to ensure the Bible is taken in the correct context at all times.