A Jew entered the Alter Rebbe’s study and said, “Rebbe, I am a simple man. Please explain to me: What is this holiday of Shemini Atzeret?”
The Alter Rebbe held his head in his hands for a moment. Then he answered:
“For a long journey, you might make a concentrate of the food and drink you will need for the way. At every stop, you mix some of the powder with water, and you have enough for that day.”
“Shemini Atzeret contains all the joy for the entire year, but in highly concentrated form. Treasure every moment!”
On Shemini Atzeret we reap our reward. The surrounding light becomes eligible to enter our soul as onner light.
The preceding days of Tishrei: Rosh Hashanah, Yom Kippur and Sukkot prepared us for this massive influx of spiritual light. We scrutinized our hearts intentions to others, made corrections and then welcomed the 7 lights to illuminate our emotional attributes.
On the 8th day 'Shemini', our soul, a vessel for these lights, is prepared to accept the huge integration of spiritual lights as inner light. The joy from this spiritual reward is expressed as Simcha Torah. We received a spiritual treasure.