Why isn't the Bible a primary source?
When researching, one relies on reliable sources that are peer reviewed, and cites those sources as support. Christians often do this with the Bible, treating it as a reliable source that has been "peer reviewed" by its authors. The Bible is viewed as the truth and the guide to reality, thus quoting from it is like a scientist quoting from a scientific journal. The difference is that the scientific journal can be criticized, reviewed further, and even refuted at some point. The Bible is not refuted as it requires its followers to maintain the Bible as a source of truth. If the Bible had plenty of outside sources to support its miracles and events then it would be credible. Christians see the Bible as truth and treat it as truth, so when someone says "you can't just use the bible as a source" the answer is "but that is my source, because it has the truth." By believing in it as the truth, and by not allowing any change or refutation to take place, the Bible is always seen as truth whether it is or not. Saying "stop using the bible as a source and use something else as a source" cannot be done, because Christianity is based on the Bible, not a system of academic peer review. The Bible fails for its lack of external support, so it relies solely on internal support. This is the same as any book that claims itself to be true regardless of any journal or review, whether it be pseudoscience, holocaust denial, conspiracy theory, or Scientology.