* It's a misquotation or paraphrase: The actual quote might be slightly different, or it might be from a less well-known book or author.
* It's a newly coined phrase: Someone might have recently created this phrase to express a particular idea.
* It's a fabrication: The quote may not exist at all.
To find the source, you would need more context: Where did you encounter this quote? Knowing the source material would be crucial to verifying its authenticity and location.