Within Egyptian magic and mythology these are sacred words of power to ward off evils and darkness. Again, in the Egyptian Book of the Dead, especially those of Am Tuat and The Book of Gates, the sun god proceeds the dragons of the Underworld (during the twelve hours of the night) calling hekau to dispel hostile forces. Such forces include abysses of darkness, streams of boiling water, appalling smells and stenches, and monsters of various shapes and sizes. A.G.H.
Source: 62, 113.