This weekend Americans celebrate the only religious holiday that belongs to people of all faiths - Thanksgiving. It is a time of expressing appreciation to God for His many and bountiful gifts. It carries no denominational connotations. On many a table of American olim, turkey will be served in nostalgia for that beautiful and meaningful day. For Jews, Thanksgiving is especially meaningful because its origins are truly Jewish. It is actually an American adaptation of Succot, the most joyous of all Jewish festivals. The Pilgrims, Christians who were particularly mindful of the Hebrew Bible, initiated Thanksgiving in the autumn of the year in appreciation of their successful harvest. They did so in imitation of the biblical autumn harvest festival of Tabernacles. In a sense, then, American Jews have three opportunities to celebrate Succot - Succot itself, Thanksgiving and Hanukka, originally known as the Succot of the month of Kislev. The idea of giving thanks is also deeply rooted in Jewish tradition. The sages often remarked that ingratitude was the greatest cause of sin. When one has plenty, it is all too easy to think that it came because of one's own work, and the richer the person, the more likely that person is to forget God, the source of all bounty. Thus the need for recitation of prayers that express thanksgiving and acknowledge a source greater than ourselves. It is not accidental, then, that the one sacrifice that the Talmud states would never be abolished is the korban toda, the sacrifice of thanksgiving. Even today when there are no sacrifices, we include Psalm 100 - called "mizmor l'toda" - a psalm of thanksgiving - in our daily service on those days when that sacrifice was brought in the Temple. For that reason it is missing from the service for Shabbat and Yom Tov, when private sacrifices were not offered. Since the sacrifice contained hametz, leavened bread forbidden on Pessah, it was not brought just before or during Pessah when its remnants could not be consumed, nor on the day before Yom Kippur because it could not be eaten that evening. This brief psalm which praises God's goodness and extols God's faithfulness and dependability was recited in the Temple when one had been saved from danger, just as today we recite a gomel blessing at those times. The sages of the Talmud taught that Psalm 107 is the source for the requirement to recite the gomel blessing at times of salvation from danger. The psalm mentions four specific times on which we are to express thanksgiving: those who go down in ships (v. 23) - after a journey by sea; those who lose their way in the wilderness (v. 4) - a long and dangerous land journey; those who cried unto the Lord and He healed them (vs. 19-20) - after illness; those bound in cruel irons (v. 10) - being freed from imprisonment. It is customary to recite the blessing after any serious illness or after having been involved in an accident or other event that might have been life threatening. It is also customary for women to recite it after childbirth. These days it might be appropriate to recite it whenever completing a journey on any road in the country. The offering of thanksgiving is described in Leviticus 7:12. The sages singled out this offering as the most important of all. In the midrash - Leviticus Rabba 9:7 - they taught: In the future all the sacrifices will be abolished, but the sacrifice of thanksgiving will not be abolished. In the future all prayers will be abolished, but the prayer of thanksgiving will not be abolished. The future was envisioned as a time of perfection when there would be no need either for sacrifice or prayer. Both of them are not needed by God. They are rather for the benefit on human beings who need to express their sins and attain atonement. That will not be necessary when humans reach perfection. But there will always be a need to express our gratitude for God's gifts and for life itself. The true basis of religious feeling is not guilt or fear but gratitude. We recite this psalm as a verbal substitute for sacrifice, thus bringing our own thanksgiving offering to God, an offering of the heart. We do not do so in response to any specific occurrence but because we are aware that all of life, life itself, is a wondrous event, an act of God's, for which we must show sensitivity and appreciation. In a sense we celebrate Thanksgiving one way or another every days of our lives. The writer is the head of the Rabbinical Court of the Masorti Movement.