This is one of my top five favorite Stephen King stories. It is from his collection, Everything's Eventual. When it appeared originally (and I'm not sure in what magazine it debuted), the acclaim was immediate. King won the 1999 O Henry award for best short story.
I like to use this one was a companion piece to Hawthorne's classic "Young Goodman Brown." In fact, King wrote this story as an homage to Hawthorne's tale (which King ranks as one of the finest pieces written in the English language).
The Man in the Black Suit