Symbols can often have double or multiple interpretations, ranging from the obvious exoteric meanings to the more esoteric ideas understood by a few. Somewhere in the middle of these two extremes can be found the hidden knowledge. Symbols conceal as much, or more, than they reveal.
Where does the masonic cube fall on this continuum? How did the hidden knowledge of the mystical qabalah influence its use in Freemasonry?
To start with, what is Qabalah? It’s difficult to define with a phrase. Even after a few decades of study I don’t think I can come up with a definition. How can you describe the indescribable?
Perhaps one could say the Qabalah is a mystical symbolic system of looking at the microcosm and macrocosm from the standpoint of the Creator. For a qabalist, there is nothing in life that is not interesting; the speck of dust on the ground, the glowing nebulas in the heavens, and the tiny living cell — all these have their message and tell a story of the Creator.
Can masons relate to this? Of course. That is why most of the early 18th century English ritualists were acquainted with the qabalistic teachings. Since many of them studied the qabalah while the masonic rituals were being written, it was likely a source for many of the signs, symbols and allegories of Freemasonry. Brother Albert Pike 33° indexed over seventy entries to the subject of qabalah in his book Morals and Dogma. 
The book indicates that the more you study the hidden meanings (or occult), it becomes clearer and clearer that everywhere in the universe, at every conceivable point in space, there is a Consciousness, which expresses through what is visible and invisible.
Pike tells us that:
“Qabalah is the key of the occult sciences.”
The qabalists used models such as the Tree of Life, The 32 Paths of Wisdom and the Cube of Space to describe the plan and processes of creation. The cube is especially significant to the themes of freemasonry. How, so?
The Qabalist’s Cube of Formation
Perhaps a good place to start is the Book of Formation or Sefer Yetzirah. It is one of the oldest treatises on qabalistic philosophy that concerns itself with the Divine creative process. It describes how the Creator literally thought and spoke everything into existence, and continues to do so. The type of creation that it shows proceeds through manipulation of the letters of the Hebrew alphabet.
I am always in awe of the Sefer Yetzirah whose short verses can easily conceal its depth and complexity. The seeming simplicity is only a taste of its mystery. The premise is that everything in the universe is directed by intelligence. The scheme of life and activity that we call evolution is in accordance with a Plan made by a Master Mind or Great Architect. 
Everything is considered to be constructed of the Hebrew letters, or at least the forces they represent. The three Hebrew Mother letters (Aleph, Mem, Shin) corresponded to the three simple letters to form the name Jah (IHV).
From Verse II of The Sepher Yetzirah:
He looked above, and sealed the Height with (IHV)
He looked below and sealed the Depth with (IVH)
He looked forward, and sealed the east with (HIV)
He looked backward, and sealed the west with (HVI)
He looked to the right, and sealed the south with (VIH)
He looked to the left and sealed the north with (VHI)
Brother Paul Foster Case, scholar and Freemason, popularized the Sepher Yetzirah through his concept of the Cube of Space using the verses in Chapters IV and V to add the tarot keys and astrological correspondences. It alludes to defining the boundaries of our perceptions. Quite a remarkable diagram, indeed!
The Divine Mind conceives the archetypal form, and then it exists in the world of ideas. A long process of human evolution has to take place before the ideal can be manifested in form, and the soul in full consciousness can achieve the archetypal form.
Some might look at the diagram and say, “so what!” Why does it matter for a Freemason
work with these archetypal ideas, specifically the cube?
The Freemason’s Perfect Stone
One possible reason is that archetypal themes underlie many of the masonic rituals. It is no coincidence that the form of a masonic lodge is a symbolic cube.
Freemason Albert G. Mackey writes:
“The lodge or collected assemblage of masons, is adopted as a symbol of the world. The solid contents of the earth below and the expanse of the heavens above give the outlines of the cube, and the whole created universe will be included within the symbolic limits of a mason’s lodge.”
In Revelation Chapter 21, the new Jerusalem is described as a perfect cube: “The plan of the city is perfectly square, its length the same as its breadth.” Also, the room known as the Holy of Holies in the Temple of Jerusalem was constructed in the shape of a cube. In the center of the room was the Ark of the Covenant that contained the Scroll of the Law.
The candidate in a masonic lodge symbolically represents one of the stones used in the construction of King Solomon’s Temple. The ritual portrays the shaping, testing and laying of that stone. Ultimately, the moral and spiritual preparation that he must undergo is to become a “living stone” in the heavenly temple.
Brother Manly Hall says:
“The perfect cube represents the personality that has had all the unevenness, roughness, and inequality polished away by experience. Such a stone is ready to become a block in the Everlasting House not built by hands but eternal in the heavens.”
If left to our own devices, our evolution and progress would be infinitesimal. But fortunately, we have teachers and perfected individuals of past ages to guide us to be perfect stones. Instead of using the working tools to build a physical structure out of stone and mortar, a speculative mason uses these same tools symbolically for spiritual, moral and intellectual development. 
In the end, what does the symbol of the cube offer? I believe it is archetypal concepts that help all of us connect with something larger. Are we not all just sculptors? Writing our own books of creation? “Becoming” perfect cubes?
“A block of marble, deep within the quarry lies. Hidden within it lies likewise a form of beauty rare. The sculptor works, patterning true to that which lies revealed unto the inner sight. He patterns true and beauty comes to life.”
– Brother Alice Bailey
What are we to make of this statement? Why would the blazing star, usually depicted as a five-pointed star, be a symbol of a sun, too? And if it is, what is different about this sun?
The process of symbolic analysis, while wrought with paradox, is actually doing something beneficial to the mind. The best summary of this idea I found in a theosophical article of the Beacon Magazine (1939) written by Alice Bailey. The article details how the mind is actually being trained when we study symbolism.
The sun is often symbolized by a symbol called the circumpunct. For those of you who’ve read the novel by Dan Brown called The Lost Symbol, you probably are familiar with what a circumpunct is. For those who aren’t familiar, it’s simply a point within a circle.
As Freemasons, the study of symbols helps us to make sense of ourselves in relation to the universe. Planetary symbols such as the sun, moon, stars, and blazing stars inspire the contemplative mind to soar aloft and read the wisdom, strength and beauty of the Great Creator in the heavens. They challenge us to dig deeper on matters of eternal significance.