Sorry mate, but that's just cultural indoctrination that made them feel that way, and the culture is intimately tied to the book.
You can downvote me all you want, but arguing that Christians' beliefs aren't tied to the bible is ridiculous. Their "deep soul" feelings are beliefs, which are formed by cultural indoctrination, and the bible is the cornerstone of the Christian culture.
For Catholics the Bible is very important but it is a map not the territory. Tradition is equally important and there is also Revelation, in the Creation, in the Universe and in our own human nature.
You're reducing everything to a book and missing two millenia of reflection upon human nature, on our purpose in this world, the thousands of books written, the millions of debates, you're missing out on a corpus of knowledge that is rich and can't be found elsewhere.
We value the map not because it's old and we are indoctrinated to, but because we see territory and roads that don't show up on the modern maps. The old map is hard to read and uncomfortable, but it leads to true places, whereas the modern maps are pretty, colorful, with good UX ("everything is allowed"), but route you to bad places and dead ends.