Dr. Kalisch, after having remarked that "the notions [of the Jews] concerning angels fluctuated and changed," says that "at an early period, the belief in spirits was introduced into Palestine from eastern Asia through the ordinary channels of political and commercial interchange," and that to the Hebrew "notions heathen mythology offers striking analogies;" "it would be unwarranted," the learned doctor goes on, "to distinguish between the 'established belief of the Hebrews' and 'popular superstition;' we have no means of fixing the boundary line between both; we must consider the one to coincide with the other, or we should be obliged to renounce all historical inquiry. The belief in spirits and demons was not a concession made by educated men to the prejudices of the masses, but a concession which all--the educated as well as the uneducated--made to Pagan Polytheism" ("Historical and Critical Commentary on the Old Testament." Leviticus, part ii., pp. 284-287. Ed. 1872). "When the Jews, ever open to foreign influence in matters of faith, lived under Persian rule, they imbibed, among many other religious views of their masters, especially their doctrines of angels and spirits, which, in the region of the Euphrates and Tigris, were most luxuriantly developed." Some of the angels are now "distinguished by names, which the Jews themselves admit to have borrowed from their heathen rulers;" "their chief is Mithron, or Metatron, corresponding to the Persian Mithra, the mediator between eternal light and eternal darkness; he is the embodiment of divine omnipotence and omnipresence, the guardian of the world, the instructor of Moses, and the preserver of the law, but also a terrible avenger of disobedience and wickedness, especially in his capacity of Supreme Judge of the dead" (Ibid, pp. 287, 288). This is "the angel of the Lord" who went before the children of Israel, of whom God said "my name is in him" (see Ex. xxiii. 20-23), and who is identified by many Christian commentators as the second person in the Trinity. The belief in devils is the other side of the belief in angels, and "we see, above all, Satan rise to greater and more perilous eminence both with regard to his power and the diversity of his functions." "This remarkable advance in demonology cannot be surprising, if we consider that the Persian system known as that of Zoroaster, and centering in the dualism of a good and evil principle, flourished most and attained its fullest development, just about the time of the Babylonian exile" (Ibid, pp. 292, 293). The Persian creed supplies us, as Dr. Kalisch has well said, with "the sources from which the demonology of the Talmud, the Fathers and the Catholic Church has been derived" (Ibid, p. 318).