I personally believe that hearing these voices is normal. "My sheep know my voice" and the bible also says satan is the accuser of brethren and that he comes to steal **** and destroy. A "roaring lion who roams to and fro throughout the earth seeing who he may devour" I personally think that the truely  "psychotic" are the ones who deny hearing such voices and would go to thier graves insisting they never heard a thing.