From Peter Levenda’s The Manson Secret.
Concerning the power of the knock:
First, magician Aleister Crowley, in his amusing and informative Magick In Theory and Practice, states,
The general object of a knock or a knell is to mark a stage in the ceremony.… The sudden and sharp impact of the sound throws the mind into an alert activity which enables it to break loose from the obsession of its previous mood. It is aroused to apply itself aggressively to the ideas which had oppressed it. There is therefore a perfectly rational interpretation of the psychological power of the knock.
Crowley belonged to the Golden Dawn, the British secret society that gave him the theoretical framework for much of his occult knowledge. Recourse to the rituals of the Golden Dawn—as published in Crowley secretary Israel Regardie’s The Golden Dawn—will show us one way three groups of three knocks may be employed.
The ritual in question is that of the Neophyte Grade, the very first initiation in the Golden Dawn scheme. The temple is arranged, according to Regardie, in Egyptian fashion, and the whole rite recalls the weighing of the soul of the recently departed against the feather of the Goddess Maat. The Neophyte wears a black hooded robe. The other officers of the temple are dressed according to their rank, but again the regalement includes Egyptian motifs.
To one side is a representation of the Evil Triad of the Egyptians: gods who are prepared to devour the entrails of the Neophyte should he be found wanting. Surrounding the Neophyte are four benevolent gods, who will protect him from the savage hunger of the Evil Triad.
At one point in the ceremony, the three main initiators perform a “battery” of nine knocks, three knocks each, while uttering the formula “Khabs Am Pekht. Konx Om Pax; Light In Extension,” one knock for each word. The initial phrase is Coptic, thus reinforcing the Egyptian character of the ritual, while the second phrase is in a “corrupt Greek” form. As for the meaning behind this, Regardie states,
This affirms the establishment of the White Triangle and therefore the Completion of the Opening Ceremony. The Mystic Words “Khabs Am Pekht” which accompany the knocks seal the image of the Light.
The Egyptian tenor of this rite is immediately suggestive to those who have read the Picknett and Prince book, because Egypt is at the heart of this mystery of The Nine.
However, the way in which the knocks are sounded is quite important; the interval between each knock is as essential as the knock and number of knocks itself. In the case of the Strieber/Glenrock events, the nine knocks are given in three groups of three, thus: 3—3—3. The number 333 has enormous significance for Qabalists (such as Madonna and Demi Moore!) as well as for ceremonial magicians in general, for it represents Choronzon, the Beast of the Abyss.
In the case of 333, we are dealing with a suspiciously empty section of the Qabalistic Tree of Life. The Tree consists of ten sephiroth or spheres, each representing some facet of creation. Dividing the top three spheres from the lower seven is what occultists refer to as Daath, or the Abyss. It represents for some the “dark night of the soul,” a necessary purging of the soul’s sins, its karma, its dross before it can continue to the three “supernals” and complete its journey to Nirvana (to mix theologies for a moment). Just as there is an “Evil Triad” waiting for the Neophyte at the very first grade of initiation—demonic forms that wish to devour the unworthy aspirant—there is a Beast waiting in the Abyss itself, as if for a second and more brutal initiation. The number of Choronzon (derived from Qabalistic numerology) is the number of that particular Beast: 333.