Arthur E. Waite - The Pictorial Key to the Tarot :
As this card follows the traditional symbolism and carries above all its obvious meanings, there is little to say regarding it outside the few considerations collected in the first part, to which the reader is referred. It will be seen, however, that the figure is seated between pillars, like the High Priestess, and on this account it seems desirable to indicate that the moral principle which deals unto every man according to his works - while, of course, it is in strict analogy with higher things; - differs in its essence from the spiritual justice which is involved in the idea of election.
The latter belongs to a mysterious order of Providence, in virtue of which it is possible for certain men to conceive the idea of dedication to the highest things. The operation of this is like the breathing of the Spirit where it wills, and we have no canon of criticism or ground of explanation concerning it.
It is analogous to the possession of the fairy gifts and the high gifts and the gracious gifts of the poet: we have them or have not, and their presence is as much a mystery as their absence. The law of Justice is not however involved by either alternative.
In conclusion, the pillars of Justice open into one world and the pillars of the High Priestess into another.
P. D. Ouspensky – The Symbolism Of The Таrot :
When I possessed the keys, read the book and understood the symbols, I was permitted to lift the curtain of the Temple and enter. its inner sanctum. And there I beheld a Woman with a crown of gold and a purple mantle. She held a sword in one hand and scales in the other. I trembled with awe at her appearance, which was deep and mysterious, and drew me like an abyss.
"You see Truth," said the voice. "On these scales everything is weighed. This sword is always raised to guard justice, and nothing can escape it.
"But why do you avert your eyes from the scales and the sword? They will remove the last illusions. How could you live on earth without these illusions?
"You wished to see Truth and now you behold it! But remember what happens to the mortal who beholds a Goddess!"