In numerous chassidic discourses1 the following question is raised: “Why do we celebrate Simchas Torah [our rejoicing with the Torah] on Shemini Atzeres, when we received the Torahon Shavuos? As such, Simchas Torah should be celebrated then, for this day [of Shavuos] made it all possible.

Chassidus answers that Simchas Torah celebrates the giving of the second set of Luchos [the tablets upon which were inscribed the Ten Commandments, the Aseres HaDibros], which G‑d gave Moshe on Yom Kippur. We are joyful on Shemini Atzeres, for Shemini Atzeres is the culmination of the month of Tishrei; on this day all the month’s events — including the giving of the second Luchos of Yom Kippur — are absorbed and internalized within each and every one of us.

Every aspect found in Chassidus, the “soul of Torah,” corresponds to its counterpart in the revealed portion of Torah. In Shulchan Aruch2 a simple and logical reason is provided for celebrating the rejoicing of the Torah on Shemini Atzeres “On this day we conclude the Torah, and it is fitting to celebrate its conclusion.”

Why, then, do we need the question in Chassidus as to why we celebrate Simchas Torah specifically on Shemini Atzeres, when a clear and concise answer is already provided in the revealed portion of Torah.

Our Sages state3 that the Aseres HaDibros — the “Ten Commandments” — contain within them all 613 commandments. Thus, as soon as G‑d gave the Aseres HaDibros, the entire Torah with all its commandments was already given. As such, as soon as the Aseres HaDibros were given for the first time on Shavuos, the Torah was seemingly concluded in its entirety. Shouldn’t such a day of “conclusion” be celebrated most joyfully?

Truly, the entire Torah and all the mitzvos were only included in the Aseres HaDibros in a concealed manner: only the actual Ten Commandments were readily perceived by all. Still, the fact remains that concealed within the Luchos was the entire Torah. Surely this is reason enough for a joyful celebration; particularly so, as even the conclusion of but a single tractate of Talmud is celebrated with great joy.4

Why is it then that on Shavuos, when the Aseres HaDibros — and thus the entire Torah —were given, and moreover “concluded,” we do not celebrate the event with the same degree of joyous gusto as we do on Shemini Atzeres?

The difference between Shemini Atzeres and Shavuos is as follows: With regard to the first set of Luchos, the Luchos of Shavuos, the entire Torah and the commandments concealed therein were granted to the Jewish people as a gift from above. This is not so with regard to concluding the Torah on Shemini Atzeres. In this instance, we have been learning Torah throughout the entire year, so much so, that by the time Shemini Atzeres comes around we have concluded the entire Torah.

This helps us understand why the joy of Simchas Torah is specifically on Shemini Atzeres and not on Shavuos:

Only when one has worked at something and has striven mightily to obtain it will he be truly joyous when he finally arrives at its conclusion. Similarly with the joy of Simchas Torah: this fulsome manner of joy is only to be obtained on Shemini Atzeres, upon concluding the Torah that we have studied — Torah that is acquired through our own toil and effort.

Shavuos, however, celebrates the “completion of Torah” we obtained as a gift — without our toil and effort. Consequently, our joy cannot be total and complete.

This is similar to the saying of our Sages5 that a person would rather have one measure of something that he himself has striven for and achieved than have nine times as much not achieved by himself but given to him by a friend. Accordingly, the effortless manner of the “completion of Torah” as experienced on Shavuos is not celebrated.

This explanation also dovetails with the chassidic explanation mentioned above, that Simchas Torah takes place on Shemini Atzeres because of the second Luchos that were given on Yom Kippur:

The general difference between the first and second set of Luchos is with regard to the Luchos themselves. The first Luchos were both the “work of G‑d and the writing of G‑d,”6 while the second Luchos were merely the “writing of G‑d,” with Moshe hewing out the actual Luchos from stone.7

This is also why the first and second Luchos differed with regard to their effect on the Jewish people and the world as a whole:

With regard to the first Luchos, our Sages say: “Had the first Luchos not been broken, Torah would never have been forgotten from Israel ... nor would any nation or people been able to exert dominion over them.” However, the second Luchos introduced a novel theme, that of “toiling in Torah.”

This means the following: With the first Luchos, the Jewish people received the Torah in the exact manner that it was drawn down from above. Thus, in the context of Divine revelation, the first Luchos are loftier than the second.

However, the second Luchos accomplished the aspect of laboring and toiling in Torah on one’s own — something that accomplishes far more than merely receiving the Torah as a gift from above.

This is why it is specifically on Simchas Torah — the conclusion and culmination of the giving of the second Luchos and the aspect of concluding the Torah as a result of one’s own labor — that we are able to truly rejoice upon concluding the Torah.

Based on Likkutei Sichos, Vol. XIV, pp. 156-160.