The Delta is an inverted triangle.. a vulva associated with the marshy fecundity cundity of ISIS, whose place this was, and whose fertility she sponsored by causing the Osirean efflux to overflow.. thus it is a 'mouth' in the sense of opening the womb, and giving birth.. to fertility, and HORUS,.
Secondly, the jaws of soon to die in ritualised sacrifice in the Americas, were cut off, leaving the tongue lolling and bripping blood...this lower jaw missing appears to be a symbolic parallel to such a 'fertility' producing situation , as the soon to die were to provide 'manna' or in the americas, PULQUE.. sacred nourishment.. to the land, 'from the other side'.
The tongue would here be the flaccid phallus, dripping 'blood/semen' into the womb, abyss..
SO.. spear up or raised blade signals virility, Osirean life energy..zest for conquering, even.
Now, 'the tongue of flame' so talked of by the xtians, seems to be implicated here..as it, signifies 'the coming forth of the word(of God).
Link these and you get a 'resurrection theology' of the spear down sacrifice of phallic blood , providing the 'fertiliser' which the otherworld requires to 'ressurect' the Osirean 'artificial' phallus ..to give birth to the 'king of the underworld'.
For him to raise the stone, to escape that tomb of all , and rise, a 'second coming'.
So opening the mouth has to do with resurrection, via a circular evaporative, condensation type CYCLE.. into the underworld thence to rebirth, via the dar world..like OSIRIS..Jesus>>Marduk.. Gilgamesh..down through the waters, up through the reeds.
Hope this grabs you .