Prayer and sacrifice are not invariably followed by success. But aid requested from human beings also is often refused, so that explanations for the lack of success are not wanting. Perhaps the prayer was not fervent enough, the sacrifice not offered in the correct manner or at the right place. Or the supplicant has offended the god; it is only to be expected that he is thus punished for the offense. Or the god, knowing his most secret failings, wishes to test his faith, his piety, in case all worldly goods and even health are lost. The gods are all-wise: who could understand them and their actions completely? Now and then, when the pious continue to suffer and the godless to prosper, religion is exposed to a serious danger. But religious faith has found the solution of this problem, not everywhere on earth, but here and there; and out of a secret doctrine of certain sects of ancient Greece this solution has become a gospel spread all over the earth: even that hope which remains unsatisfied at the time of death will find its realization. Man’s soul is eternal, is only temporarily united with the body, and when separated from it will continue to live forever. The pious must prepare himself for the future life by turning away from bodily pleasure toward God, by suffering. The godless, who has failed to prepare himself, finds eternal punishment waiting for him. Under primitive cultural conditions, when everybody has to do every kind of labor for himself, the same régime is applied to the gods. They do not differ much in their abilities, although one can do this, the other that, somewhat better. They are an unorganized crowd like mankind, fighting each other and forming alliances for this purpose. When human societies become established, the gods become differentiated. There are masters and servants, various professions. Complications arising from such occurrences as subjection of one nation to another and a consequent assimilation of their religions, change but little the trend of this development. Of greater influence are the growth of morality and the advance of scientific knowledge. When man establishes a moral ideal for himself, he applies it to his gods. His gods become moral examples. They no longer require bloody sacrifices, but a clean heart and good deeds. And since there is only one morality, and morality is the chief attribute of Deity, there can be only one God. All those great religious teachers who contributed to the moral development of religion, the Jewish prophets, Zoroaster, Plato, accepted monotheism.