Is The Bible A Legitimate Source?
Doesn't the Bible have a particular view on things? Certainly, it is promoting a religion. How then can we trust what it says? Can it be used in real historical research? What do we do with it?
These are legitimate questions, and I certainly understand why people ask them. However, I don't think most people are aware of the materials that historians regularly have to work with. For example, consider Tacitus, one of the best historians in the ancient world and an excellent source on Roman history. Tacitus records miracles in his writings, and while historians generally don't believe that these occurred, they're still able to use his works for historical study.
Or, consider Plutarch, another Roman historian wrote biographies of many famous and important figures. He often covered the same events multiple times when writing different biographies (because several of these people were involved in them). When you compare them, what you find is that many of his accounts contain the same sort of errors the Gospels contain. You know how one story tells it one way, and another story tells a little differently? Yet, secular historians still consider Plutarch to be a good source.
What we need to understand is that historians don't simply read ancient document and assume that everything in them is true. They try understand why the author wrote what he did and ask the question "Was this really what happened or not?" Sometimes they look outside of the documents for external verification, and sometimes they look inside the documents for internal verification. Going into these methods in detail goes beyond what I'm trying to do here. I'm simply trying to make the point that historians do not simply accept all commentary from the ancient world uncritically. Every single piece is evaluated to try to understand whether or not it's legitimate.
So, when a historian looks at the Bible, he's not really going to see a whole lot that's new (at least nothing that challenges his ability to do history). Historians are used to evaluating ancient sources they don't agree with, they’re used to considering any potential bias the author has, and trying to determine what probably happened in the past.
That means that whether you believe in the Bible as the word of God or not, it can still be used as a set of historical sources. (Remember, the Bible wasn't compiled until later. The various parts were written separately). What most people don't realize is that professional historians give serious consideration to what the Bible says, whether they trust in what it says or not. So, when people ask for sources about early Christianity apart from the Bible, they're really throwing away the best sources - the same sources that professionals rely on.