The masses of ancient Egypt believed in many gods. But there was another religion, known only in the elite circles, priests and educated.
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 or 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 about 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"
"Unknown is his name in heaven"
"He doth not manifest his forms; vain are all representations"
"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. 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. That's why in 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. In fact, any god could have been called by the name of almost any other, except for evil gods.
Doesn't this all sound a whole lot like the God of the Bible? Ancient religions descended from the original religion. The original religion of the human race is recorded most thoroughly in the Bible. But fragments of that religion entered into the ancient pagan religions, with various modifications and gradual deviations.
So is it a surprise that often times, biblical principles are found in ancient texts of pagan religions? It doesn't mean the Bible was copied from these pagan texts. It means that there were indeed revelations from God to the first people. As the original human race diverged into the different regions of the earth, they carried the religion they learned from Noah. But since they soon forgot the One true God, their religion gradually deviated from the original religion. Instead of worshiping the One true God, they created various smaller gods, from the qualities of One God.
Sources:
Ancient Egypt By George Rawlinson, M.A., print, London 1886
Image source: http://www.bible-history.com/ibh/Egyptian+Gods/Other+Gods/Egyptian+Gods+and+Goddesses