The commandment to kindle Chanukah lights is similar to the commandment regarding the affixing of a mezuzah, in that both are to be placed at the doorway of one’s house or courtyard, and both are to be on the outside.1

Nonetheless, there is a major difference between the two: The mezuzah is placed on the right side of the doorway, while the Chanukah lights are placed on the left.2 Also, the mezuzah is placed on the outside, not for the purpose of those outside, but because that is the place where a person’s house or courtyard begins.

By contrast, Chanukah lights are to be placed on the outside because their purpose is to illuminate the outside, the “public domain,” i.e., the domain of unholiness (as opposed to the “private domain,” the domain of holiness, G‑d’s domain).3

Our Sages tell us that the commandment to place a mezuzah on our door is equivalent to all other commandments, for it encompasses all the commandments.4 Understandably, the aspects of the mezuzah’splacement are also found in all the other commandments, since specific details — the individual commandments — are always similar to their general principle, the commandment of mezuzah.

We therefore observe that —similar to mezuzah, which is placed on the right — most commandments are accomplished with the right hand.5 Indeed, some commandments — such as the bringing of offerings6must be performed with the right hand.

Additionally, most commandments are not bound up with the external level of the “outside.” Moreover, there are some commandments that must be performed while a person is “inside,” and even those that may be performed while a person is “outside” have no specific connection to the outside: their performance is not limited to a specific place.

Accordingly, we may conclude that the commandment of kindling Chanukah lights — which must be performed on the left and specifically on the outside — differs not only from the commandment of mezuzah, but from the overwhelming majority of commandments.

Why does kindling the Chanukah lights differ so markedly from the other commandments?

The difference between kindling Chanukah lights and the other commandments is similar to the difference between positive and prohibitory commandments: Positive commandments can be performed only with permissible things,7 while prohibitory commandments are specifically performed through (refraining from doing) prohibited things, or with objects that derive their nurture from unholiness.

The reason for this is as follows: The nature of the Divine illumination that is drawn down through a positive commandment is finite. As such, it must be drawn down within an appropriate receptacle. It therefore cannot descend into unholiness, for that is not an appropriate vessel for this finite degree of spiritual illumination.8

In contrast, the illumination drawn down by obeying a prohibitory command is infinite in nature. Correspondingly, it is not drawn down through man’s act of making a proper receptacle, but is brought about by not doing that which is prohibited.9 Since this illumination knows no bounds, it can be drawn down even to the lowest levels, affecting them as well.10

This same quality is inherent in the commandment to kindle Chanukah lights: Performing this mitzvah draws down such a great degree of spiritual illumination that it is possible to refine, illuminate and elevate even the “public domain.”

In fact, kindling Chanukah lights possesses greater qualities than the performance of prohibitory commandments, for it retains the quality of a positive command: Performing a prohibitive command negates the prohibited matter — that which is prohibited is cast aside. However, by kindling Chanukah lights, the “public domain” becomes illuminated, similar to the illumination accomplished with an object through which one performs a positive commandment.

Based on Likkutei Sichos, Vol. V, pp. 223-225.