What are we celebrating?
שבעת ימים תחג…והיית אך שמח
You shall celebrate for seven days…and you shall be only joyful
The holiday of Shemini Atzeres is one of those interesting festivals with no associated paraphernalia. Rosh Hashanah has the Shofar, Sukkos has the Sukkah, Pesach has Matzah. The celebration of each festival seems to be accompanied with some sort of item or activity to add a focus to the festivities. They are usually associated with some event, which is the cause of the celebration. What are we celebrating on the holiday of Shemini Atzeres? In fact, the Torah, with regards to Sukkos, tells us to be “only” joyful. The gemarra expounds the extraneous word “only” to be teaching us that Shemini Atzeres is also a time of joy. What are we joyful about on Shemini Atzeres?
One explanation could be that we are celebrating the completion of all the various mitzvos of the past month. On Rosh Hashanah we blew the Shofar and coronated Hashem. On Yom Kippur there’s the Temple service, and the requisite repentance. On Sukkos there was the sukkah and the four species. There’s also the various offerings that were brought on each of the holidays. Having successfully fulfilled our obligations is certainly a cause for celebration.
In fact, whenever a person completes a mitzvah, they should rejoice. Another example of this is with the mitzvah of ma’aser sheni, which completes an entire series of agricultural mitzvos. A person with a field of produce first performs the mitzvos of leaving pe’ah (a corner of the field), shichchah (forgotten produce), and leket (gleanings) for the poor. Once harvested, there’s the mitzvos of separating terumah and ma’aser rishon for the Kohen and Levi (respectively). Upon completing all of these mitzvos comes the mitzvah of separating ma’aser sheni and eating it in Jerusalem. The Torah even commands rejoicing when eating it there. Part of this celebration comes from the culmination of all of these agricultural mitzvos. Perhaps the reason it was instituted to read about ma’aser sheni on Shemini Atzeres was allude to this idea. This also could explain why it was instituted to conclude the Torah at this time.
May we only know joy and happiness this festival, and let that spirit continue with us for the rest of the year.
Good Yom Tov!
 Based on Derashos Chasam Sofer HaShalem Shemini Atzeres VeSimchas Torah § 10 (first printed in Chiddushei Chasam Sofer Sugyos (5653) § 2)
 Deuteronomy 16:15
 The other is Shavuos
 Sukkah 48a; Pesachim 71a
 Usually the word אך is used to exclude things, not to include things (Rosh Hashanah 17b with Rashi s.v. כאכין ורקין; Yerushalmi Berachos 9:5). Why is it being used here to include Shemini Atzeres in שמחה? The Chasam Sofer addresses this contradiction in many places, with various explanations. The Vilna Gaon (Kol Eliyahu to Deuteronomy loc. cit.; Devar Eliyahu Likkutim Sukkah 48a) provides a simple explanation: Before Shemini Atzeres there’s the holiday of Sukkos, which has many mitzvos to rejoice over. In contrast, Shemini Atzeres, as already stated, has no mitzvos. So in reality, the joy felt on Shemini Atzeres is less than that of Sukkos. I wonder if this fits with the following idea from the Chasam Sofer
 Deuteronomy 12:7
 The Torah reading is ibid 14:22 – 16:17, which starts with עשר תעשר (Megillah 31a, see Rashi ad. loc. s.v. קורין כל הבכור)