“A job will never satisfy you all by itself, but it will afford you security and the chance to pursue an exciting and fulfilling life outside of your work. A calling is an activity you find so compelling that you wind up organizing your entire self around it — often to the detriment of your life outside of it. There’s no shame in either. Each has costs and benefits.”
While I think there’s a spectrum between a job and a calling as defined here, this strikes me as generally right. But there’s a third piece here that Lewis doesn’t get into. I’ll call it a career, for lack of a better term (I’m afraid using that word will muddy what I’m trying to say, but I trust you’ll take my point). If a job is something unsatisfying that provides security and time, and a calling is something internally compelled and all-consuming, then a career is the unfortunate amalgamation of the two, taking only the troublesome aspects of both: something unsatisfying but all-consuming, leaving no time to pursue anything potentially worthwhile.