The Qabalah is a precise system of mysticism that describes universal laws and shows us students of the divine how to put them into actual use in daily life. The Qabalah often uses sacred symbols to help us realize its teachings. Symbols sink into your subconscious and become part of your hard-drive almost immediately; and this happens just by gazing at them.
The Tree of Life is a powerful and ancient symbol and is the central symbol of Hermetic Qabalah. It is composed of ten spheres called sephiroth (spheres in Hebrew) and 22 connecting pathways. The pathways are lines drawn between and connecting the ten spheres to each other. When the sephiroth and the paths are all joined, they form the Sacred Tree of Life.
The ten sephiroth represent divine attributes, and are often called the divine emanations of Deity. The sephiroth are singularly referred to as sephirah (meaning sphere). The ten sephirot and the twenty-two paths comprise what is called the Thirty-Two Paths of Wisdom. It is significant to note that there are 22 letters in the Hebrew alphabet, considered a sacred alphabet by which the Creator made the Universe. There are also 22 major arcana cards in the Tarot deck.
The Tree of Life is the single most important symbol in Hermetic Qabalah and is considered highly important in those schools that have a more mystical flavor rather than a dogmatic one. The Tree of Life is arranged in a pattern that places the sephiroth in juxtaposition, so that the energies of each sephirah are counterbalanced with the sephirah on the opposite side of the tree. The ten sephiroth emanate from the Three Negative Veils of Existence. The Negative Veils represent various stages of abstract nothingness.
According to Qabalists, the Universe is separated into four close but distinct "worlds". Each of these "worlds" came into existence with the creation of the sephiroth (spheres) by the Path of the Flaming Sword. The four worlds each formed out of the previous world, each evolving from the previous world. As the worlds formed they became more substantial eventually reaching physical manifestation in the very last world.
1. BIG BANG AFTERMATH: Rasheet ha-gilgalim, meaning "the First Whirlings", assigned to Kether
2. ZODIAC: Mazlot, meaning "the Stations", represented by the twelve Zodiac star constellations and assigned to Chokmah.
3. SATURN: Shabbatai, meaning "the Seventh", represented by Saturn and assigned to Binah.
4. JUPITER: Tzedek, meaning "the Righteous", represented by Jupiter and assigned to Chesed.
5. MARS: Madim, meaning "Might", represented by Mars and assigned to Geburah.
6. SUN: Shemesh, represented by Sol and assigned to Tipharet, sometimes spelled Shamash, the Sumerian Sun God.
7. VENUS: Nogah meaning "the Shiner", represented by Venus and assigned to Netzach.
8. MERCURY: Kohab meaning "Star", represented by Mercury and assigned to Hod.
9. MOON: Levanah meaning "the Moon", represented by Luna and assigned to Yesod.
10. EARTH: Olam Yesodot meaning "the World of Foundations", represented by the Sphere of the Elements and assigned to Malkuth.
The above information has been taken from Qabalah Study Hall and does differ (in some parts) to the interpretation of the QBL as taught by the Temple of the Dark Moon.