The new regulations have created 'a devil of' a problem [=a very difficult problem] for many small businesses.
He had 'a devil of a time' getting another job. [=he found it very difficult to get another job]
The shoes look great, but they're 'the devil' to walk in. [=they are very difficult to walk in]
(..) and caress her." Yes. My dear Mrs. Hunter, you have arthritis, don't you? -Yes, I do, Eli. -Yes. The devil is in your hands, and I will suck it out. Now, I will not cast this ghost out with a fever for the new spirit inside me has shown me I have a new way to communicate. (..)2007 There Will Be Blood