Significance of Re-stau
Re-stau, meaning "Gate of the funereal passages," represents the entrance to the afterlife and transition from life to death. It's a narrow way with doors, not always accessible to Ra. Re-stau is associated with Osiris, whose heart rejoices there, and Horus. It's a place of homage, where ways are opened, and connected to the strength of Osiris. Re-stau designates tomb passages leading to the other world, originally referring to the cemetery of Abydos.
The below excerpts are indicatory and do represent direct quotations or translations. It is your responsibility to fact check each reference.
Classical concept of 'Re-stau'
From: The Book of the Dead
(1) Re-stau is referenced as the place within which the speaker has beheld the dividing of the persea trees.[1] (2) Re-stau is the location from which Nehau comes forth, and Ani declares he has not defrauded offerings.[2] (3) Re-stau is the location of the great godlike rulers Horus, Osiris, and Isis, where the heart of Osiris rejoices and the heart of Horus is glad, contributing to the peace of the east and west.[3] (4) A location or entity to which homage is paid, where a way is opened, and associated with the strength of Osiris.[4] (5) Re-stau, meaning "Gate of the funereal passages," is represented by a pylon with doors, symbolizing the entrance to the afterlife and the transition from life to death.[5]
From: The Egyptian Heaven and Hell
(1) RE-STAU is the corridor through which AFU-RA travels, which bends upwards, passing by the secret abode of SEKER, and then descends to its former level, leading to where AFU-RA is received by the MORNING STAR.[6] (2) This entity is identified as the main corridor in the FOURTH DIVISION, featuring doors at the end of each section, and is part of the route through which AFU-RA travels.[7]
From: The Gods of the Egyptians Vol 1
(1) It is a narrow way with three doors, divided into three parts, one of which Ra does not enter.[8]
From: The Book of Am-Tuat
(1) RE-STAU is a corridor that slants across the topmost division to the lower side, touching the line dividing the first and second sections.[9]