The ultimate fate of the souls of human beings who had departed to the Tuat must always have been a matter of speculation to the Egyptians, and at the best they could only hope that they had traversed the long, dark, and dangerous valley in safety.
The same may be said of numbers of the gods, who in very early times were believed to possess a nature which closely resembled that of men and women, and to be in danger of extermination in the Tuat. Of the gods the only one about whose successful passage of the Tuat there was no doubt was Ra, or according to the priests of Amen, Amen-Ra, for he rose each morning in the East, and it was manifest to all that he had overcome whatsoever dangers had threatened him in the Tuat during the past night.
This being so, it became the object of every man to obtain permission to travel in the boat of Ra through the Tuat, for those who were followers of Osiris could disembark when it arrived at his kingdom, and those who wished to remain with Ra for ever could remain in it with him. To each class of believer a guide to the Tuat was necessary, for up to a certain place in that region both the followers of Osiris and the followers of Ra required information about the divisions of the Tuat, and knowledge of the names of the Halls and Gates, and of the beings who guarded them and who were all-powerful in the land of darkness.
For the worshippers of Amen, or Amen-Ra, the BOOK AM-TUAT was prepared, whilst the followers of Osiris pinned their faith to the BOOK OF GATES. From each of these Books we find that the Sun-god was not able to pass through the Tuat by virtue of the powers which he possessed as the great god of the world, but only through his knowledge of the proper words of power, and of magical names and formulae, before the utterance of which every denizen of the Tuat was powerless.
Osiris had, of course, passed through the Tuat, and seated himself on his throne in the “House of Osiris,” but even he would have been unable to perform his journey in safety through the Tuat without the help of the words of power which Horus, the son of Isis, the son of Osiris, had uttered, and the magical ceremonies which he had performed.
Words and ceremonies alike he learned from Isis, who, according to a later tradition, obtained the knowledge of them from Thoth, the Divine Intelligence. Now if Osiris and Ra had need of such magical assistance in their passage through the Tuat, how much greater must have been the need of man!
E.A. Wallis Budge, The Egyptian Heaven and Hell, 1905, pp. 91-3.