Oh, a rather complex question for me, Lori.  Is my source external or internal?  It’s like asking me if I’m introverted or extraverted. I read a lot of books (which is supposed to mean I am introverted) but if you stop to look at the kind of books I read–at least 80% of my reading is about people (novels, psychology, the arts) not things.  So I’m an extroverted introvert?  I seem to be both!  Some people score 80/20 or 70/30 on the introvert/extrovert dimension.  I’m like 45/55!  External input prompts my writing and so does internal energy.  It’s very mixed up for me and I think, at this point, not very relevant.  I write because I want to write and I’ll use whatever kind of inspiration (external or internal) comes to me.  But, I can think of situations where this might be a good question.  Such as, am I writing to get approval?  To get published?  To become famous?  Because one of my parents was a famous writer??  Are these questions examples of external motivation or internal motivation?  Could be both. 
Oh, lord, I think I’ll go on to the easier question.  Is the source of my inspiration divine?    I would not say so, but I can understand why artists/writers/musicians have said this.  There have been rare occasions (usually when writing poems) when I feel that I (my ego, conscious self) has not written something.  Another part of me (beyond my ego) has written it.  Because it comes out about 98% finished!  Maybe I have to give it a title, but the rest of the work was done before I picked up the pen to write!  Plop!  There is it!  A complete little story in the form of a poem.  I wish I could figure how I did it and do it more often!  (The conscious self/ego wants that control!)  Most of my writing though (fiction or non-fiction) comes in pieces.  A little bit here, a little bit there.  It needs time to grow.  Sometimes I get endings before beginnings, or middles before beginnings & endings.  Sometimes it’s like putting a puzzle together or quilting.  This dialogue goes here, etc.  Or, to use another metaphor, (used first by someone else but I can’t remember whom) and this I could believe, there’s always a river or stream of creativity going thru us–24 hrs a day, 365 days a year, (and dreams are part of this river too), but we (our conscious self) can only go swimming in this river part of the time.  Do not mourn the time we are not swimming though, for we are human and therefore need to eat/sleep, care for children, pay the mortgage, etc.  Indeed, if we didn’t do those things we wouldn’t be able to “go swimming” at all.  So celebrate–and come on in, the water’s just fine.

Cheshire

P.S.  Honest truth.  I wrote this before I saw the photo Literary Bohemian posted with her writing.  Go check it out–it’s a beautiful nature scene.