“Another prayer of special interest is that which forms Chapter XXXB.
This is put into the mouth of the deceased when he is standing in the Hall of Judgment watching the weighing of his heart in the Great Scales by Anubis and Thoth, in the presence of the Great Company of the gods and Osiris.
He says: “My heart, my mother. My heart, my mother. My heart whereby I came into being. Let none stand up to oppose me at my judgment. May there be no opposition to me in the presence of the Tchatchau [The chief officers of Osiris, the divine Taskmasters]. Mayest thou not be separated from me in the presence of the Keeper of the Balance. Thou art my Ka (i.e. Double, or vital power), that dwelleth in my body; the god Khnemu who knitteth together and strengthened my limbs.
Mayest thou come forth into the place of happiness whither we go. May the Shenit officers who decide the destinies of the lives of men not cause my name to stink [before Osiris]. Let it (i.e. the weighing) be satisfactory unto us, and let there be joy of heart to us at the weighing of words (i.e. the Great Judgment). Let not that which is false be uttered against me before the Great God, the Lord of Amentet (i.e. Osiris). Verily thou shalt be great when thou risest up [having been declared] a speaker of the truth.”
In many papyri this prayer is followed by a Rubric, which orders that it is to be said over a green stone scarab set in a band of tchamu metal (i.e. silver-gold), which is to be hung by a ring from the neck of the deceased. Some Rubrics order it to be placed in the breast of a mummy, where it is to take the place of the heart, and say that it will “open the mouth” of the deceased.
A tradition which is as old as the twelfth dynasty says that the Chapter was discovered in the town of Khemenu (Hermopolis Magna) by Herutataf, the son of Khufu, in the reign of Menkaura, a king of the fourth dynasty. It was cut in hieroglyphs, inlaid with lapis-lazuli on a block of alabaster, which was set under the feet of Thoth, and was therefore believed to be a most powerful prayer.
We know that this prayer was recited by the Egyptians in the Ptolemaic Period, and thus it is clear that it was in common use for a period of nearly four thousand years. It may well be the oldest prayer in the world.
–E.A. Wallis Budge, The Literature of the Ancient Egyptians, 1914, pp. 26-7.