This day of the festival of matzos (Siddur).
Outside the Land of Israel, today is observed as the last day of Passover. In Israel, Passover lasts seven days, so it ended yesterday.
This discrepancy has its origin in the beginning of the dispersion of the Jewish people, before a set calendar had been established. In those days the High Court in Jerusalem declared the first day of a new month, based on sighting the new moon. Jewish communities outside of Israel could not know whether the High Court of Jerusalem had determined the previous month of Adar to be one of twenty-nine or of thirty days, so that they did not know which day was the first of Nissan. Not knowing when Passover began, communities in the diaspora observed an additional day.
Since we now have an established calendar, why do we continue this practice? The months are set; we have no doubt when Passover begins.
The Talmud states that because our condition in the diaspora is always one of uncertainty, the possibility exists that Jewish communities may lose contact with the established calendar. Hence, Jews have preserved the tradition of keeping an additional day. This idea is not farfetched; ninety percent of Jews today live in a different country than did their ancestors a century ago.
Why, then, is Israel different? Has history not taught us so painfully that we have no certainty of permanence, even in our own homeland? Do Jews in Israel have some guarantee?
The answer is that living with uncertainty in the Land of our roots is still far superior to the security of being firmly established in the diaspora. The observance of the additional day of the festival is a reminder that our roots and our future, as well as our past, are in the Land of Israel.