The Kedushat Levy on Sukkot

The following is a teaching from Rabbi Levi Yitzhak of Berdichev. It is taken from the middle of a drash on Passover, but it concerns Sukkot and the day of Shmini Atzeret. His prooftext is Numbers 29:35:

לה  בַּיּוֹם, הַשְּׁמִינִי--עֲצֶרֶת, תִּהְיֶה לָכֶם:  כָּל-מְלֶאכֶת עֲבֹדָה, לֹא תַעֲשׂוּ.

35 On the eighth day you shall have a solemn assembly (atzeret): you shall do no manner of work;

It is known that all that which is drawn down and flows in from the Blessed Holy Creator happens through the seven middot that channel those influences through to us. This is why the holiday of Sukkot is eight days, because seven days correspond to these seven middot and the eighth day corresponds to becoming the receiver of what flows in from above. Therefore the eighth day of Sukkot is called "Atzeret" as is written "On the eighth day your shall have an atzeret." (Numbers 29:35). That is to say that which is drawn down and flows in from the Blessed Holy Creator during seven days of Sukkot through the seven middot, is then contained and absorbed in the eighth day through one's ability to become the recipient of these influences. This is the meaning of "you shall have an atzeret:" what flowed in from above will stop in "you", in other words you will receive it and it will be absorbed in you.

And this happens during the holiday of Sukkot, because then the entire community of Israel gains the ability to receive the fullness of inflows from the Blessed Holy Creator by having elevated themselves on Rosh Hashanah and Yom Kippur with great devotion to God and having cleansed themselves of materiality and physicality and reached the moment of the elevation of all the worlds. Then, during the days of the Sukkot holiday, new inflows and enlightenment are drawn down for them through the seven middot and by means of their elevation to God on Rosh Hashanah and Yom Kippur they become fit to be vessels that receive all the inflows from the seven days of Sukkot on the eighth day and are then able to hold (la'atzor) and take in the inflow into themselves.