Question: My antagonist sends my protagonist a note that says "See no evil, hear no evil, speak no evil".

Obviously, this is the story of the the three wise monkeys, but I'd like this to relate to something different in my fantasy universe.

I've written a sub-story, that will act as 'Lore' for my universe. I want this sub-story to utilise this saying instead; the story bears resemblance to the sentiment of the three wise monkeys but is otherwise unrelated.

The story will be 'common knowledge' to the characters, like some popular fables and stories are to us (the ones that everyone knows). The protagonist will summarise the story briefly in conversation to explain how it links with the note. Later in the book, I'll challenge this retelling by looking at a 'how it really happened' style revelation.

What are the repercussions of re-imagining a fable/story like this to fit it within my fantasy universe? I guess I'd like to know if the reader would be okay with this, or if they'll dislike it.

Answer: 
Myths, fables, fairy tales, classics are incorporated, remixed and reused over and over in all kinds of media. See a [related question](https://writers.stackexchange.com/questions/6189/whats-the-significance-of-ancient-mythology-in-literature). The repercussions will be that people will notice, and will expect some twist, something to make the old story new. If you fail to deliver that, you will disappoint them.

Your story will be shoehorned by critics as a "*retelling*" but that's not really a bad thing. It's just like if you put vampires in, it's automatically labeled "horror", doesn't mean vampires or horrors are bad - it's just that if you want to maintain a different identity of the story, it will be difficult.

Expectations will be higher. People are more forgiving for crappy original stories than to crappy retellings - but if you write it well, you have nothing to worry. This applies only to the bottom-scrappers.

But other than that, you're fine. As long as the tale is old enough not to be covered by copyrights, you're just doing what half the "industry" does.
read "another day another dungeon" and its sequel "one quest hold the dragons" for a good example of how to incorporate character storytelling. I particularly like the contradictory explanations of greep. not all of the accounts of the origin/memories of greep are particularly consistent with the theme of the book (humor), but because of the placement, and discussion of the storys they work well.

In your story you need to have not only told the story of the three bears, but little blue boots, and ravenlocks and the three panthers to pull off what you are trying.