While the first night of Passover commemorates the redemption from exile in Egypt, the final day celebrates the future Redemption, which G-d will bring about through Moshiach.
The connection between the first and the last redemption is also gleaned from the verse: "As in the days when you left Egypt, I shall show you wonders [during the final Redemption]."
Our Rabbis ask: Why does the verse say "As in the days when you left Egypt," when the Exodus took place on one day, as the verse states: "Remember this day on which you left Egypt."
On the day the Jewish slaves left Egypt they achieved the status of free people. This transition, however, is an ongoing experience that requires constant meditation on the concepts of slavery and freedom. A person's ruminations must have a salutary effect on his daily conduct.
This is why spiritual redemption from all straits and limitations that constitute spiritual Egyptian exile is an ongoing process, notwithstanding the fact that the Jews' physical Exodus took only one day.
This is expressed by our Sages when they state: "In each and every generation and on each and every day, every man is obligated to see himself as if he had gone out from Egypt on that very day."
Man's viewing the Exodus from Egypt as a continuous process will lead to daily improvement in conduct as well - as befits a free man.
Both the first and the final redemption involve the liberation of all the Jewish people. Just as the Exodus encompassed the entire nation and resulted from the Jews' collective service, so will the future Redemption liberate all Jews from exile, and it too will result from our collective efforts.
This collective liberation and effort came about during the Exodus as a result of the effort of each Jew, who first liberated himself from his own spiritual exile.
And so with the final liberation: the efforts of each and every Jew in redeeming himself from spiritual exile will result in the collective redemption of all Jews from the final exile.
In practical terms, the lesson from the above is that each and every Jew is entrusted by G-d with a unique mission that he, and only he, is capable of accomplishing.
He cannot rely on someone else to fulfill that mission for him, for the other individual is entrusted with his own mission.
On the other hand, each person must also realize that he is part of a collective - the Jewish nation. His mission is thus of vital importance not only to himself but to all the Jewish people.
Fulfilling his mission as an individual thus helps the Jewish people fulfill their mission as a collective whole. Ultimately, each Jew's personal redemption from spiritual exile leads to the collective redemption of all Jews from the final exile.
Adapted from the works of the Lubavitcher Rebbe, Rabbi Menachem M. Schneerson, of righteous memory. (Likkutei Sichos Vol. XXII pp. 258-263.)