Of course God wrote it ultimately. But who physically *wrote out* God's words, in Greek, out on the parchments that got copied, recopied and passed around in the ancient Christian world?
One of my favorite lines from St. Paul is at the end of one of his letters (Galatians?) where he says, "See with what LARGE LETTERS I am writing to you with my own hand? This is what my writing always looks like. This is the way I write!" I'm sure if he had a (/sarcasm) tag, he'd have used it :-).