This article was written originally as a draft for private study, consequently all my indebtedness to other scholars, such as Dr J. L. Ainslie, Dr T. W. Manson, Dr T. F. Torrance, etc., is not noted as it ought to be. That it owes much to such men is freely admitted, so I hope that this acknowledgment will be accepted as adequate. Further, it was prepared for a group of theologians, with the result that a considerable background-knowledge is taken for granted. Its purpose was simply to form a brief historical survey as a basis for further study.