The subject matter of this essay, in so far as it is concerned with what is called the Obediential Potency, naturally finds no exact place within a course of philosophy properly so-called, when later the student proceeds into formal theology, the divine science, it is customarily assumed that the matter has been already sufficiently studied in the preliminaries to theology. It finds its right place within the Science of fundamental theology, or Apologetics, which deals with the Praeambula Fidei, the motives of credibility and similar material. Sometimes, however, its central importance fails to receive adequate attention, and its essential significance, while not being entirely overlooked, rarely obtains the emphasis which is its due. The following pages are intended briefly to co-relate it with the growth of divine action in the soul, and to suggest that the endowment of divine grace progressively proceeds in correspondence with the development of the obediential capacity.