Besides the common popular religion, the belief of the masses, there was another which prevailed among the priests and among the educated. The primary doctrine of this esoteric religion was the real essential unity of the Divine Nature. The sacred texts, known only to the priests and to the initiated, taught that there was a single Being, "the sole producer of all things both in heaven and earth, himself not produced of any," "the only true living God, self-originated," "who exists from the beginning," "who has made all things, but has not himself been made." This Being seems never to have been represented by any material, even symbolical, form. It is thought that he had no name, or, if he had, that it must have been unlawful to pronounce or write it. He was a pure spirit, perfect in every respect--all-wise, almighty, supremely good. It is of him that the Egyptian poets use such expressions as the following: "He is not graven in marble; he is not beheld; his abode is not known; no shrine is found with painted figures of him; there is no building that can contain him;" and, again: "Unknown is his name in heaven; he doth not manifest his forms; vain are all representations;" and yet again: "His commencement is from the beginning; he is the God who has existed from old time; there is no God without him; no mother bore him; no father hath begotten him; he is a god-goddess, created from himself; all gods came into existence when he began." The other gods, the gods of the popular mythology were understood in the esoteric religion to be either personified attributes of the Deity, or parts of the nature which he had created, considered as informed and inspired by him. Num or Kneph represented the creative mind, Phthah the creative hand, or act of creating; Maut represented matter, Ra the sun, Khons the moon, Seb the earth, Khem the generative power in nature, Nut the upper hemisphere of the heavens, Athor the lower world or under hemisphere; Thoth personified the Divine Wisdom, Ammon perhaps the Divine mysteriousness or incomprehensibility, Osiris the Divine Goodness. It is difficult in many cases to fix on the exact quality, act, or part of nature intended; but the principle admits of no doubt. No educated Egyptian conceived of the popular gods as really separate and distinct beings. All knew that there was but One God, and understood that, when worship was offered to Khem, or Kneph, or Maut, or Thoth, or Ammon, the One God was worshipped under some one of his forms or in some one of his aspects. He was every god, and thus all the gods' names were interchangeable, and in one and the same hymn we may find a god, say Ammon, addressed also as Ra and Khem and Turn and Horus and Khepra; or Hapi, the Nile-god, invoked as Ammon and Phthah; or Osiris as Ra and Thoth; or, in fact, any god invoked as almost any other. If there be a limit, it is in respect of the evil deities, whose names are not given to the good ones.