Skeptics (atheists, agnostics, secularists and our beloved theologically liberal “Christians”) often feed us the line that if a thing can’t be found outside the New Testament, it is not to be believed at all. My argument back is to say “so what?” It is irrelevant if something is not attested outside the New Testament because there is no necessity for that to be the case in the first place.
The only reason that skeptics question its reliability (i.e., in light of the overwhelming “secular” evidence of its profound historicity) is because of their prior hostility to Christianity and because the Bible is a religious book and therefore, supposedly untrustworthy by that fact alone (which is mere prejudice).
But that doesn’t follow. Why can’t a document be religious and historically reliable, too? Of course it can, and the Bible is. So it’s really a non-issue, based on the following two fallacies or errors (the second building upon the falsehood of the first):
[Error] 1) The Bible has not been confirmed in its historical accuracy by non-biblical “objective” fields of inquiry (historiography and archaeology).
[Fallacy] 2) Therefore, everything referenced in the Bible must be found also outside the Bible or it is automatically historically questionable.
Folks like this love to cleverly force us into accepting their false premises, in order to get us concerned and worked up about fallacious arguments that they build upon false premises; but we need to go right to the root of the problem, and attack the fallacies they are assuming and foisting onto us. This is a classic example.