All Jewish Holidays are intertwined and interwoven.
On each day of Passover the Torah reading discusses all of the Biblical holidays of Passover, Shavuot and Sukkot. Indeed, even the Holiday of Purim is remembered on Passover. On the second day of Passover, Haman, the villain of Purim, was hanged. [Purim itself is celebrated not because of Haman's execution but because eleven months later the Jewish people successfully defended themselves against their would-be attackers. But, nevertheless, Haman's death on Passover suggests some connection between these two holidays.]
The connection between Purim and Passover is mentioned in the Talmud: Both are holidays of redemption; Passover from slavery to freedom and Purim from a death threat to life.
But what is the connection between Passover the "season of our liberation" with Shavuot the "season of the giving of our Torah" and Sukkot, the "season of our rejoicing?"
The answer is that without freedom one cannot be a true recipient of the Torah. As long as one is subjugated to another master one cannot properly accept the yoke of G-d's commandments. A human being can and must have but one Master.
Without freedom one cannot, likewise, experience joy. Besides the fact that slaves usually have to endure much physical and emotional pain and abuse and cannot be happy, there is a deeper reason why they cannot feel joy. Joy is an emotion of expansiveness. How can a person who is confined and constricted be capable of experiencing the openness and expansiveness of joy? To be free thus is to allow one's soul to be open and filled with exhilaration and happiness.
[One can demonstrate how the Giving of the Torah at Shavuot is also the basis for freedom and happiness; and how happiness of Sukkot is also the foundation for the receiving of the Torah of Shavuot as well as the freedom associated with Passover. But these connections we will leave for another time.]
Passover is a paradigm for the future Redemption, particularly during the last two days of Passover when we focus our attention on the future.
It follows then that the Messianic era that will be ushered in by the coming of Moshiach will not only make us totally free but will also facilitate the revelation of the deepest secrets of the Torah that were heretofore hidden from us. While the Exodus from Egypt enabled the Jews to be receptive to the exoteric and more down-to-earth aspects of Torah, the future Redemption will enable us to be receptive to the esoteric and heavenly dimension of Torah.
The Messianic Age will also introduce us to dimensions of joy that were never known previously. The utter freedom and expansiveness we will experience will open up our souls to levels to unprecedented levels of joy. May we see the realization of this joy this Passover.