What is Shemini Atzeret?
Not quite Sukkot, not quite its own holiday.
Reprinted with permission from Celebrating the Jewish Year (Jewish Publication Society).
Although Hoshanah Rabbah may technically be the "last day" of Sukkot, the Rabbis decided to treat Shemini Atzeret (and Simhat Torah) as a part of Sukkot, because its significance is unequivocally informed by Sukkot itself.
Two cryptic references in the Torah cause the confusion about the status of Shemini Atzeret. In both Leviticus and Numbers, God commands that the eighth (shemini) day--referring to Sukkot--is to be a "sacred occasion" and an atzeret, generally translated as "solemn gathering."
What is Atzeret?
The inherent problem is that no one really knows exactly what atzeret means. Possibly it comes from the word atzar, meaning "stop," and thus implies that we are to refrain from work. On the other hand, atzeret may also be defined by its textual context, which implies that it is some sort of deliberate extension of the prior seven days. This lack of verbal clarity is likely the reason why the rabbinic sages seemed to struggle with the precise meaning of the holiday.
The earliest rabbinic reference to Shemini Atzeret calls it yom tov aharon shel ha-hag, the last day of the festival. The Talmud (Taanit 20b-31a), however, declares, "The eighth day is a festival in its own right." At the same time, the Talmud (Taanit 28b) attempts to distinguish it from Sukkot, as there are 70 temple sacrifices given throughout Sukkot, compared to only one given on Shemini Atzeret. (This distinction was only theoretical as the Temple had been destroyed five centuries prior to the redaction of the Talmud.)
Cutting through this puzzle, the most appealing depiction of the holiday may be that of Samson Raphael Hirsch, a 19th-century Orthodox rabbi who lived in Germany. He infers the meaning of the holiday from the word atzeret, which he renders as "to gather" or "to store up." Accordingly, on this eighth day of Sukkot, the final day of celebration, we must store up the sentiments of gratitude and devotion acquired throughout the entire fall holiday season; nearly two months will pass until we celebrate another holiday, that of Hanukkah.
Different from Sukkot
Although the observances of Shemini Atzeret generally share the characteristics of the rest of Sukkot, there are four significant differences. The first is that there is no more shaking of the lulav and etrog. Second is that although we have our meals and recite Kiddush in the sukkah (though customs vary), we no longer say the blessing to sanctify us through the commandment to dwell in it, as we did the previous seven days. The third is that in the synagogue, after the Torah reading, we recite the memorial prayer (Yizkor).