Sample from THE OMER AND THE KABBALAH (From the Preface.)

SEFIROT: THE ENERGY FOR TRAVEL

Kabbalists assigned each week of the Omer a quality called a Sefirah (pronounced Seff-ee-raw), the plural of which is Sefirot (pronounced Seff-ee-roat, with a meaning related to the English “spheres.")  In modern physiology, the Sefirot have been identified as "energy centers" or "nerve ganglia" located in specific areas of the human body. 

Sefirot also find a parallel in the "Chakras" of the Hindu-Sanskrit spiritual lexicon.  A basic tenet in Kabbalah holds that the Sefirot make up the Etz Chayim (Aits Chay-yim), the "Tree of Life."  This imaginary tree represents the structure of your spiritual self as well as the structure by which God holds the Universe together. 

During the Omer count, the Tree of Life invites you to open up each of its Sefirot in the sense of "opening your heart." This expression is right on target because your heart is right at the center of the seven Sefirot of the Omer count.  If you can open up your heart, you can open up your other Sefirot as well.Going a step further than associating a Sefirah with each Omer week, the kabbalists also imbued every day of each week with its own Sefirah; the combination enriches the blessing for each day by enabling the user to visualize how the week’s Sefirah is influenced when the day’s “small” Sefirah is inserted into it.  It is a bit like seeing how the coffee in a large mug changes in color by just adding some cream.