What is the source of the following quotation?  Please supply
diacritical marks where you know they go.

"Oh tenebreux et troubles, nos coeurs humains, meme les plus
sinceres!"

Sounds like Blaise Pascal, but I'd like to know for sure.

I searched a site which appeared to have all Pascal's Pensees, and it
does not appear to be from the Pensees, although it could be from
something else by Pascal.

I couldn't tell about diacritical marks because they are often not
present online.

Good luck,
microme-ga