Time is a tyrant. It plants a "One Way Only" sign on the road of life, another dictating "No Stopping, No Standing", and mercilessly enforces both rules without equivocation. It wrenches us away from our past and holds off our future behind a wall of ignorance, making compost of our most treasured moments and a mockery of our predictions.
We might overthrow political dictators, cure diseases, overcome poverty; but if we want to be free, we must conquer time. For of what use would it all be, if we remain imprisoned within a sliver of present, sliced so thin that anything we have and everything we are already was or hasn't yet been?
That is why Passover, the festival of freedom, is predicated upon the power of remembering. Memory is our answer to the tyranny of time. Reclining at the seder, eating the matzah and the maror and drinking the four cups of wine, we ingest history into our very flesh and blood, tasting -- and becoming -- the bitterness of our slavery, the triumph of our Exodus, the faith that carried us from Egypt, and the commitment we entered into at Sinai. Time's bounds fall away that night; the past becomes current, history becomes now.
But if only the roadblock to the past were lifted, ours would be only a partial victory. If time surrendered only one of its frontiers on Passover but maintained its blockade of the future, we'd be only a half-free people, masters of our past but prisoners of the unknowable to-come.
That is why Passover has two parts. The "first days" with its seders and its reliving of history, and the "final days" with its messianic themes -- days that herald the divine goodness and perfection which, the prophets promise us, is the end-goal of creation and the fulfillment of our present-day lives.
There is even a Chassidic custom, instituted by the Baal Shem Tov and further developed by the Rebbes of Chabad, to conduct a "mirror-seder" in the closing hours of the last day of Passover, complete with matzah and four cups of wine. These are hours, say the Chassidic masters, when time relinquishes its last hold upon our lives; when the future, too, can be remembered, and the Era of Moshiach tasted and digested as the Exodus is on the seder night.