The opening will be of John Charling sitting in his study preparing for a service. As he turns the pages of his bible he turns to a certain verse that he couldn’t move on from. At first, he reads it to himself then he starts to read it in a whisper, all the while he hears another voice but to obscured to understand at first. Locked in an almost catatonic like state the obscured voice gets louder and louder till it’s an imperious wail, “Cleanse, you must kill.” The room seems to begin to spin uncontrollably horrified he stands up knocking over his chair and scattering papers all over the room. As he stands he falls against the wall both arms sprawled to catch himself he then grabs his head with his left hand and at first just puts his right palm on his bible with his elbow straighten to aid in his effort to brace himself, but the terror fell on him so heavy it dragged him down. He feels his knees start to get weary and give way. IN doing so his right elbow collapses and he slumps down with his right cheek landing on the top of his right hand, then slides and falls to his right side in the floor. When he comes to he’s surrounded by his secretary and his remaining staff. There is a click as the tape recorder turns off and then Dr. Andrews clears her throat and asks, “Is this where it begins?” The only response she gets is a nod yes.
Yes, this is possible. Thomas Harris's Red Dragon opens with Jack Crawford asking Will Graham to join his FBI team. After a bit of conflict (Will's wife is against the idea), Will agrees. Plot-wise, totally acceptable for an opening chapter.
I doubt if this opening scene really contains the story's turning point, as by nature that happens further down the line. I mean, at this moment you have nothing to turn. But you've got a good hook there, as now we want to know if he eventually acted on the mysterious voice and what he will tell the doctor we presume is a psychiatrist. Me, I also wonder what verse gave him such problems, and if he forgot the basic interpretive principle of "context, context, context."
I would say, if the main character ends up killing somebody because of what the voice told him to do, THAT would be the turning point. That's where things can't go back to the way they were before. Just hearing voices isn't a turning point, unless the story is about an otherwise normal man finally getting to see a psychiatrist. I define turning point as a place in the story where things happen that can't be undone or reversed. I guess I treat it as a 'pivotal point' or a 'point of no return.' It is kind of a semantic exercise, though. I agree with @OJB that this is an okay place to start the story, providing we get a handle on what John was like before this happened to him.
I think its like a crisis ... different "how to write your book" formulas use varying terms Personally I like to write organically without following a structure set by someone else, but i digress
