The final day of Chanukah is customarily called Zos Chanukah, “This is Chanukah.”1 The simple reason for this name is that the Torah reading for the final day of Chanukah contains the passage “Zos chanukas hamizbeiach,” “This is the dedication of the altar”2 — andthe word Chanukah is rooted in the word “chinuch,” or “dedication.”

However, since Jewish custom is itself Torah,3 and the entire eighth day of Chanukah is termed “This is Chanukah,” we also understood that this day “is Chanukah,” i.e., that the last day of Chanukah encapsulates all of Chanukah.

What is so significant about the eighth day of Chanukah that it is considered to embody the entire festival of Chanukah?

We find4 that Beis Shammai and Beis Hillel — the Torah academies of Shammai and Hillel — differed with regard to the manner of kindling the Chanukah lights. Beis Shammai maintained that the lights should be lit in descending order: on the first night, eight lights are lit, on the second night seven, and so on until the final night, when only one light is lit.

Beis Hillel, however, maintains that the lights are lit in ascending order: on the first night one light is lit, on the second two, etc., until on the final night all eight lights are lit. The halachah favors Beis Hillel.

The reason for the disagreement is as follows:5 Beis Shammai is of the opinion that we look at matters as they are in their potential state. Thus, on the first day of Chanukah eight lights are lit, for this day encompasses, in potential, all the days of Chanukah that follow.

Beis Hillel, however, maintains that we look at things as they exist in actuality. Therefore, the number of lights lit are in accordance with the actual number of days of Chanukah — i.e., on the first day only one light is lit, for in actuality it is but the first day of the festival, and from that day on an additional light is lit each day.

Our Sages relate6 that the word “Chanukah” is an acronym for “Eight lights are to be lit, and the law is in accordance with the opinion of Beis Hillel.” That the name of the holiday itself is said to emphasize the opinion of Beis Hillel clearly indicates that on Chanukah, particular emphasis is placed on the actual rather than on the potential.

What is it about Chanukah that emphasizes the superiority of the actual over the potential?

The argument as to whether one should lean towards potentiality or actuality is in truth a dispute regarding Torah and mitzvos in general. G‑d gave His Torah and mitzvos to the Jewish people. Torah and mitzvos therefore reflect aspects of both the Giver and the recipient, G‑d and the Jewish people.

We thus find that on the one hand Torah is not subject to impurity even when studied by an impure individual, for it remains G‑d’s Torah — it retains the aspects of the Divine.7 On the other hand, a Torah master may forego his own Torah honor, for the Torah is considered to be his property — it possesses the aspect of the recipient, the Jewish people.8

As a result, there are two ways in which Torah can be manifest within this world — reflecting the perspective of the Giver, or reflecting the framework of the receiver, the Jewish people.

Beis Shammai holds the view that Torah primarily reflects the perspective of its Giver. They therefore say that matters of Torah and mitzvos should always be viewed in their potential state, since from the perspective of the Giver, all of actuality already exists within the Divine potential.

Beis Hillel, however, is of the opinion that most important is the consideration of how Torah and mitzvos affect the Jew as he actually exists as an imperfect created being within this world. Therefore, until a matter has obtained its actual fulfillment, nothing has been accomplished — we must look at matters of Torah and mitzvos as they exist in actuality.

If this is so regarding all other aspects of Torah and mitzvos, says Beis Hillel, how much more so with regard to Chanukah, for Chanukah is particularly connected with the recipient, which is man. This is because Chanukah differs from all other Torah festivals in that it is of human, Rabbinic origin. Thus, Chanukah in particular reflects Torah and mitzvos from the perspective of the recipient — the aspect of the actual rather than the potential.

This is why it is only on the final day of Chanukah — when all eight days and lights have been actualized and lit — that we say: “This is Chanukah.”

Based on Likkutei Sichos, Vol. XXV, pp. 243-250.