Question: The phrase "Man will believe anything, as long as it's not in the Bible" is attributed to Napoleon on many sites but there are no further details (date, context,etc.) available, nor a trace of primary sources.

Some examples:
[AZ Quotes](https://www.azquotes.com/quote/1056429), [Quote Fancy](https://quotefancy.com/quote/870652/Napoleon-Man-will-believe-anything-as-long-as-it-s-not-in-the-bible), [Love Expands](https://loveexpands.com/quotes/napoleon-bonaparte-700294/).

Answer: 
To a bit more history here, there's a 1998 book
*Soaring and Settling* by [Rita Gross](https://en.wikipedia.org/wiki/Rita_Gross), which has a different take/version (p. 43):

> 
> I am just as frustrated that many Caucasian Buddhists, reasonably sophisticated in their assessments of certain elements of Christian tradition that are woefully out of date, will believe anything as long as it is said by a Tibetan lama.
> 
> 
> 

I suspect it's this passage or something similar that was the basis of the post-2000 broader but similar pronouncements.

Regarding Napoleon, he [generally](https://journals.openedition.org/rh19/622) found Catholicism useful, but Protestantism not so much. So it's quite unlikely he would have said something that simplistic about the Bible. On the other hand, Napoleon was/is more often demonized or derided in Protestant circles, which is a more plausible reason why the quote might have been attributed to him in such circles.
Napoleon born: [1769](https://en.wikipedia.org/wiki/Napoleon)

First known attestation: [1716](https://books.google.com/books/about/The_Free_holder_Or_Political_Essays.html?id=Yu8Gf39YGgkC&printsec=frontcover&newbks=1&newbks_redir=0&source=gb_mobile_entity#v=onepage&q=Learned%20divine&f=false)

Conclusion: NO! (Not the first at least.)

It's that easy to prove this negative. But in its place we only find the allegation that it was really [Charles II](https://en.wikipedia.org/wiki/Charles_II_of_England) who said it, referring to [Isaac Vossius](https://en.wikipedia.org/wiki/Isaac_Vossius):

> 
> This Learned Divine, said he, is a very strange Man: He believes every thing but the Bible.
> 
> 
> 

([Alternative link to the quote](https://quod.lib.umich.edu/cgi/t/text/pageviewer-idx?cc=ecco;c=ecco;idno=004856157.0001.000;node=004856157.0001.000:6;seq=45;page=root;view=text))