The idea that the deceased could air his grievances about someone else in the hereafter, and also be called to account for his own actions, was known in Egypt from as early as the 4th Dynasty. In addition, the Pyramid Texts contain references to a judicial investigation into the king's conduct. The collapse of the Old Kingdom played a crucial role in the development of these ideas into a divine tribunal which everyone had to pass before qualifying for a life after the physical death. Besides concerns about the material precautions needed for continued existence after this life, the belief in a judgement in the hereafter also grew during this period, with everyone being judged by the same standards regardless of rank or position - had they or had they not lived in accordance with Maat. This concept, first explicitly formulated in the Instructions to Merikare, lasted until well into the Late Period.
According to this concept, the instrument of justice is the weighing scales - the human heart is put into one side of the scales, after all, it knows everything about the actions of its owner, and weighed against a feather, the symbol of Maat. If the scales are balanced, then the judgement is favourable, but if the heart is heavier than the feather, the deceased has to suffer a second death. From the New Kingdom on, this second, definitive death was symbolized by the Devourer, who waits impatiently under the weighing scales. Anubis accompanies the deceased to the judgement hall and operates the scales; Thoth ensures that the correct procedures are followed and notes the outcome of the judgement. The office of supreme judge was originally performed by the sun god Re, who on the basis of his relationship with Maat was regarded as an impartial judge, and whose verdict could not be influenced by magical means. He was supported by the Ennead, who formed the judicial tribunal. Later it was Osiris who was regarded as the supreme judge. He was supported by forty-two judges of the dead whose task was also to punish. In addition to Osiris, Amun, Atum or Geb could also function as the supreme judge. With Osiris as the judge, it was possible for every deceased person to achieve the judgement "true of voice" by becoming identified with him. The mortuary literature includes magical formulae to favourably influence the judgement, and next to spells such as the "Negative Confession" or Spell 30b in the Book of the Dead which refers to the deceased's heart, we find illustrations of a positive outcome designed to bring about the desired result.