Answer: Really there aren’t that many. Everything is derived from the fact that every day is new, every month is new, every year is new, and every hour is new for a person! These seemingly astronomical changes are, in fact, internal, spiritual. All matter results from changes among the spiritual forces that influence our world, and so changes appear among the levels of the still, vegetative, animate, and us.
In other words, the reason for all of the changes is the rotation of the Sefirot through which the Light passes. The Light influences and acts on our universe and the result is the matter in our world. So if a person wants to be connected with the entire creation, every moment is of immense value for him. Besides that, he can divide every moment within it into a multitude of moments. This means that the possibility exists for one second to come alive for him! And in this way he expands himself.
The Jewish holidays are characterized by giving us a sensation of uniqueness to every moment in time, in every Sefira that participates in the passage of Light. So every moment is unique, and especially the holidays are the general significance of a period of transition. There are three big holidays that are derived from the spiritual level: Pesach (Passover), Shavuot, and Sukkot, which are called Raglaim (feet), which are when people went to Jerusalem.
Tisha B’Av (9th of Av) symbolizes the destruction of the Beit HaMikdash (Temple), meaning the revelation of great egoism that is later corrected during all the rest of the holidays. Because of the force of Tisha B’Av, it is placed against all the rest of the holidays, so its intensity is huge.
In contrast to Tisha B’Av, at the other end of this cycle, is the holiday of Purim. Besides this, there are a few other related minor holidays: Chanukah and Lag Ba’Omer.
We indicate the beginning of every month according to the cycle of the rotation of the moon, for our cosmic and spiritual state depends upon two luminaries: the moon and the sun. So the Hebrew calendar is constructed according to the cycles of the rotation of the sun and the moon, between which is the Earth, while the Christian calendar considers only the rotation of the sun and the Muslim calendar considers only the rotation of the moon.
The Jewish New Year is the beginning of human correction because this holiday symbolizes the birth of Adam HaRishon (the First Man), from which we begin our calculation. The birth of Adam is the birth of the human because Adam was the first to discover the Creator and to begin to resemble Him. So the beginning of the year for us is a spiritual holiday.
The goal of the cycle of the holidays is that the most “frightening” of the holidays, which is Tisha B’Av, will become the greatest holiday in the world, when all of the evil will be gathered together and defeated by the good.
From KabTV’s “Conversations with Michael Laitman” 5/13/15