> People give meaning to things. Bible, Quran, etc have meaning only because people express that meaning.

A fairly central part of the philosophy of quite a few religions is that there is a God who is quite capable of giving meaning to things independently of humans. Not everyone views these as "that's nice" documents. I mean, there's a bit in the Bible (1 Corinthians 15) that says that if the stuff in the Bible is actually true, then it's the most important thing in the world, but if it isn't, then there really isn't any point paying any attention to it at all.

> A fairly central part of the philosophy of quite a few religions is that there is a God who is quite capable of giving meaning to things independently of humans.

I think it's like that with all religions. I'd like to speak a little with that god about some meanings.

> Not everyone views these as "that's nice" documents.

You say that those people give a meaning to those documents?

Addendum:

What I mean is that when there is no people who express some meaning, it ceases to exist. If there appeared a god before me to give me a new meaning for something, I would accept it as given from god. But none did so far, ALL meanings are currently expressed by people as far as I know.

Consider the statement "2 + 2 = 4". If there were no people to express what that meant, it would still be true and have meaning.

If no one existed, who would consider it true? It would have meaning to who? If you showed that statement to some old tribe which doesn't know numbers beyond 3 (Pirahã), they would not know what you mean. If you showed that without translating to some Romans, they would probably have to think about meaning of that sequence of characters. Some ideas (like mathematics or existence of a higher being) are pretty natural for humans, doesn't mean that those ideas mean anything to anyone besides humans, without people there is no meaning, just some clumps of atoms.

People believe different things about the Bible. She me people think swearing on it is making a promise to God.

Does the person swearing on Sagans book think Sagan is going to hold them accountable to a broken promise?

I conclude that person thinks Sagan will hold them equally as accountable as God would if they’d chosen His book.

Yes, I think it's equivalent and Sagan will held them as accountable as your chosen god. For "the person", you can just ask directly.

They might be doing it intending that they will remember and endeavour to hold true to some message of the book.