Beginning on the second night of Passover we will count the Omer, culminating 49 days later with the festival of Shavuot. The Talmud calls Shavuot “Atzeret,” the same name as the eighth day of Sukkot. This hints to us that Shavuot, the culmination of counting of the Omer, can be seen as the “eighth day,” i.e. an extension of Passover. The festivals of Passover and Shavuot are inextricably linked; in fact the Torah does not provide a specific date on which to observe Shavuot; the pasuk simply says to “count 49 days from Passover” (which we begin to do on the second night of Passover).
However, the connection between Passover and Shavuot goes much deeper than. Passover is a celebration of the Jewish people’s exodus from Egypt. The Haggadah tells us that in order to fulfull the mitzvah of the seder each of us needs to do our best to put ourselves in a frame of mind to experience the breaking of the bonds of slavery like our ancestors. But this “escape from” is only half the story. Once we have escaped, where are we going toward?
This is where the counting of the Omer and Shavuot come in. The exodus from Egypt is no more than casting off the shackles of servitude. Counting the Omer (and the Kabbalistically influenced process of deep reflection on our character traits during this time) is how we move from “freedom from” Egypt, to “freedom to” fulfill our relationship with the Divine.
Pesach and the exodus from Egypt are the “what.” Counting the Omer, Shavuot, and receiving the Torah are the “why.”