If you're working to build a unique culture staffed with people who make a difference, consider:
"If you're not looking for a job, this might just be the job for you"
and, once the job is under consideration:
"You know, this might not be a good fit for you."
Most jobs seek the low bidder, the person desperate enough to work cheap, or to sign up right now, and most jobs stress that 'this is a great place to work' (implying 'great for everyone.')
When you staff a place with idiosyncratic miracle workers who in fact have plenty of other options, it's a lot harder to fill those jobs, but a lot more likely you'll build something extraordinary once you do.
Posting this on Valentine's Day is not ironic. As important work gets ever more personal, so does hiring… "Who's available?" is not a good selection driver for work or for life.
[The flipside of the situation is also true: I frequently see job descriptions that are basically impossible to fill as specced. If you can't think of a single individual that you've worked with over your entire career that would be the perfect fit for this job–and work on the terms you're prepared to offer–there's something wrong with the job you hope to fill. Wishing is not a strategy.]