 That's an unanswerable question if you're going to go by the Bible alone, because the Bible nowhere tells you. I feel like Dwight Schrute right now. The Bible nowhere tells you which books belong in the Bible. So, I mean, if there were time, what I would do is I'd walk you through to show you how those 27 books that you have in your New Testament were inspired by God, not the Catholic Church, that's for sure.