All these religions, however, have a history, a history more deeply interesting than the history of language, or literature, or art, or politics. Religions are not unchangeable; on the contrary, they are always growing and changing; and if they cease to grow and cease to change, they cease to live. Some of these religions stand by themselves, totally independent of all the rest; others are closely united, or have influenced each other during various stages of their growth and decay. They must therefore be studied together, if we wish to understand their real character, their growth, their decay, and their resuscitations. Thus, Mohammedanism would be unintelligible without Christianity; Christianity without Judaism: and there are similar bonds that hold together the great religions of India and Persia--the faith of the Brahman, the Buddhist, and the Parsi. After a careful study of the origin and growth of these religions, and after a critical examination of the sacred books on which all of them profess to be founded, it has become possible to subject them all to a scientific classification, in the same manner as languages, apparently unconnected and mutually unintelligible, have been scientifically arranged and classified; and by a comparison of those points which all or some of them share in common, as well as by a determination of those which are peculiar to each, a new science has been called into life, a science which concerns us all, and in which all who truly care for religion must sooner or later take their part--_the Science of Religion_. Among the various classifications[2] which have been applied to the religions of the world, there is one that interests us more immediately to-night, I mean the division into Non-Missionary and Missionary religions. This is by no means, as might be supposed, a classification based on an unimportant or merely accidental characteristic; on the contrary, it rests on what is the very heart-blood in every system of human faith. Among the six religions of the Aryan and Semitic world, there are three that are opposed to all missionary enterprise--Judaism, Brahmanism, and Zoroastrianism; and three that have a missionary character from their very beginning--Buddhism, Mohammedanism, and Christianity. The Jews, particularly in ancient times, never thought of spreading their religion. Their religion was to them a treasure, a privilege, a blessing, something to distinguish them, as the chosen people of God, from all the rest of the world. A Jew must be of the seed of Abraham: and when in later times, owing chiefly to political circumstances, the Jews had to admit strangers to some of the privileges of their theocracy, they looked upon them, not as souls that had been gained, saved, born again into a new brotherhood, but as strangers גְּרֵיים‭‭, as Proselytes (προσήλυτοι); which means men who have come to them as aliens, not to be trusted, as their saying was, until the twenty-fourth generation.[3]