It was taught by W.E. Butler, who got it from Dion Fortune, who learned of it when she recommended Regardie to the Bristol Temple of the Stella Matutina, a Golden Dawn offshoot , It appears to have been an adaptation of an Egyptian spell to Set a Guardian before the door of a Tomb. It is still powerful after many centuries and can be used to place your Guardian if you Adapt to suit yourself. According to Israel Regardie this spell is from the "HARRIS PAPYRUS", circa 1152 BCE, he gives the verbatim translation in his book: "The Tree of Life", which differs slightly.
https://en.wikipedia.org/wiki/Papyrus_Harris_I
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Here is the Original Spell: The Dog of Defense
"Arise Dog of Defence that I may instruct thee in thy duties.
Be thou ever watchful to the North and the South, the East and the West,
behind thee and above thee, and below thee and around thee.
Take thy watch from the setting of the Sun to the coming of the dawn,
and stand guard as I have instructed thee."
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N.B.
Some practitioners may choose an artificial Elemental or "servitor", instead of one of an actual Elemental, e.g., a Slyph, Undine, Salamander, or Gnome. You can choose one that best describes your Intended type of Protection. If a "servitor" is created decide upon it's length of service in advance.
A Guardian is normally an Elemental whose shape has been Changed by Your Intention into whatever shape you decide upon. No Elemental should Ever be forced into perpetual work of any kind, hence the Time Limit here of a Year and a Day. After that you should erect a New Guardian. The Dog of Defense is effective if you are away from home, and feel the need for protection of your Sanctum / Temple Space. It is Highly Effective, and if you happen to be even a latent materializing medium, you can end up with something very Tangible.
You should decide on a Name and Form for Your Guardian, (which you visualize, and does Not have to be a Dog!). Now you're ready for an Adaptation of this spell for your Sanctum, Temple (or any other space) and "might" go something like this:
My redaction of this spell:
"Arise ...."Name Here".... to defend this space, that I may instruct thee in the guarding of this sacred place. Look to the East and the South, to the West and the North, Above thee and Below thee, and from whatever quarter evil may strike.
(Add any additional instructions here).
Thy standing is for a Year and a Day, through both the Darkness of Night, and the Light of Day. When thy time is done depart to thine own place and may you be blessed with the amount due to thee".
Have fun redacting this spell and make it useful for your own needs!

