Shavuot is one of the three Pilgrimage Holidays mandated by the Torah, and yet the text tells us very little about the holiday or how it is to be observed. Even the date on which it is celebrated is left undefined. Instead, Shavuot is described only by reference to what came before it. The nature of the holiday became the subject of intense debate among rival factions during the Second Temple era.
In fact, this controversy was part of a much larger debate which threatened to split the Jewish nation along sectarian lines. The split hinged on a major difference of opinion over the nature of Jewish society and its foundation texts: Is the Torah a fixed text, unchangeable for all time, or is it a living document meant to be reinterpreted in the light of changing circumstances?