The Union Haggadah, ed. by The Central Council of American Rabbis , at sacred-texts.com
Among the ceremonials which nurtured the Jewish idealism of generations, a place of peculiar charm is held by the Seder, celebrated on the Passover Eve, and repeated on the following night by those who observe the second days of festivals. Literally, the name means the Order of the service. The ritual provided for the service is known as the Haggadah, that is, the Narrative of the Passover. The ceremony grows out of the several injunctions in the Pentateuch for the Israelite to Relate to his children the story of the Exodus from Egypt, and to explain to them the meaning of the rites and symbols connected with the celebration of the Passover.
In the Seder are blended, in happy combination, the influences which have contributed so much toward inspiring our people, though scattered throughout the world, with a genuine feeling of kinship. Year after year, the Seder has thrilled them with an appreciation of the glories of their past, imbued them with an heroic power of endurance under the severest trials and persecutions, and quickened within them the enthusiasm of high ideals of freedom.
It has helped to forge "not easily dissoluble links" between the individual and the Jewish people. In his tribute to the poetic beauty of the Seder, Heinrich Heine expressed a sentiment, evidently founded on his personal experience: "It thrills the heart as though one heard the lilt of some sweet lullaby. Even those Jews who have fallen away from the faith of their fathers in the mad pursuit of other joys and other glories are moved to the very depths of their being when by chance they hear again the old Passover melodies once so dear to them."