"Passover is a festival without a clear ending.
It receives its spiritual significance from the Torah given seven weeks later, on Shavuot.
The gap of time between these two festivals symbolizes the wandering and the search, the transition from a negative reality of physical labor - and nowadays, of spiritual enslavement - to an essential quest for the meaning of that freedom.
On Shavuot we receive the answer and come to understand the reason for the Exodus.
Only then do these two festivals become one unit at whose core is the Jew searching for his raison d'être.
Such a person cannot be content with the mere negation of his existing reality.
He must strive to learn his true purpose through the answer that was revealed to us at Mount Sinai."
From an essay, "Shavuot: Understanding The Purpose of Our Freedom" by Rabbi Adin Steinsaltz