There is much discussion in Chazal as to the origin and significance of mitzvos derived in the gemara. Chanukah is no exception. Upon first glance, it seems that the mitzvah of Chanukah is m'd'rabbanan. However, upon closer examination we notice that the sources are not so clear on this issue. When the gemara explains the establishment of the holiday of Chanukah, we must attempt to understand whether this holiday originates from a d'rabban or a d'oraisa.

The Mishnah Berurah (670:1) understands the gemara simply to mean: "The Rabbis of that generation enacted that these days, beginni ng with כ"ה כסלו, be celebrated as days of joy and praise... and this is a rabbinic mitzvah like the reading of the megillah on Purim." This understanding would in fact be the basic one most people would have when asked about the source of the mitzvah of Chanukah. After all, how could a mitzvah enacted more than a millennium after מעמד הר סיני possibly be rooted in the Torah?

The Chasam Sofer has a fascinating and innovative approach to the mitzvah of hadlokas ner Chanukah. He explains: "Establishing a holiday on the day a miracle occurred is derived from a kal va 'chomer m'd 'oraisa. Therefore, in my humble opinion, Purim and Chanukah are mitzvos d'oraisa . However, what is required to fulfill these chiyuvim, whether it be משלח מנות or hadlokas neros Chanukah or any formal remembrance, is determined by the Sages. One who does not perform any act of remembrance for Chanukah or Purim transgresses a mitzvah d 'oraisa; however, one who performs an act of remembrance on Purim or at least one day of Chanukah, even if it is not the one sanctioned by the Sages (i.e. hadlokas ner Chanukah or k'rias megillah, for instance) has only transgressed a mitzvah d 'rabbanan."

The Chasam Sofer seems to go as far as to say that one could fulfill his chiyuv d'oraisa of Chanukah through any act of celebration related to Chanukah, even by singing Chanukah songs and eating latkes. The opinion of the Chasam Sofer is based on a gemara in Megillah (14a). The gemara states: "48 nevi'im and 7 nevi’ot prophesied for Am Yisroel, and they neither subtracted nor added one mitzvah on to those written in the Torah except for k'rias megillah. How did they derive this mitzvah? R' Chiya bar Avin said in the name of R' Yehoshua ben Korcha: Just as we say shirah when going from slavery to freedom, so too we should say shira when going from death to life.

From this gemara, we see a clear source m’d oraisa for the mitzva of krias megillah. Although the Sages clearly enacted many rabbinical mitzvos, this gemara differentiates between k 'rias megillah and the others, equating k 'rias megillah with mitzvos d'oraisa. The Chasam Sofer extends this gemara to all situations where one is required to give thanks over a miracle that has occurred to him. Chanukah, he assumes, should .therefore be included as well. In fact, Rashi on the aforementioned gemara also implies that Chanukah is included, comparable to Purim in this way.

The Harerei Kedem סימן קפג points out that the Rambam (Hilchos Chanukah 3:3-4) repeats himself when comparing Chanukah and Purim. First the Rambam writes that hadlokas neros Chanukah is a mitzvah d 'rabbanan just like reading the megillah, clearly teaching that the mitzvos of Chanukah and Purim are both m 'd 'rabbanan. In the following halacha, the Rambam says that anyone obligated in k 'rias megillah is also obligated in hadlokas ner Chanukah.

Why did the Rambam need to repeat himself? The Harerei Kedem explains that the first halacha teaches that the actual mitzvos of Chanukah and Purim are mitzvos d 'rabbanan. The second halacha supplements this by saying that even though the mitzvos are only m 'd'rabbanan, the actual chiyuvim of Chanukah and Purim are truly m'd 'oraisa – just as !he chiyuv of k 'rias megillah is m'd'oraisa (as indicated by the gemara in Megillah 14a), so is the chiyuv of hadlokas neros Chanukah also m'd 'oraisa.

The Netziv (עמק שאלה בראשית שאילתא כ"ו אות א) disagrees with this approach, opting for the Mishnah Berurah's approach. The Netziv holds that Purim and Chanukah are both completely m'd 'rabbanan. He explains that the gemara that derives a mitzvah m'd'oraisa to celebrate Purim deals only with the celebration at the time of the actual salvation, but not l'doros, for future generations. When we celebrate Purim in our homes, we are only fulfilling the takkanah d'rabbanan, not the original chiyuv d 'oraisa which was only applicable at the time of the actual neis.

Alternatively, one can assume like the Chasam Sofer that the mitzvos of k 'rias megillah and hadlokas ner Chanukah are truly m'd 'oraisa. This does not necessarily force us to assume, however, that one can fulfill his chiyuv d’oraisa by singing HaNeiros Hallalu or Maoz Tzur. This is similar to a discussion regarding tefillah. The Rambam rules that there is a chiyuv d 'oraisa to pray every day, a chiyuv which is fulfilled through any prayer that contains שבח בקשה והודאה, praise , request, and gratitude. Rav Shach maintains in his ספר אביעזרי (תפילה א:א) that this was only true before the Sages qualified the chiyuv d'oraisa. By qualifying the chiyuv d 'oraisa, the Sages not only enacted that a person should fulfill this obligation through Shemoneh Esrei, but that he can only fulfill his obligation through Shemoneh Esrei. We may assert, along the lines of Rav Shach's opinion regarding tefillah, that once the Sages enacted a specific way of fulfilling the celebration of Chanukah, we no longer have the liberty of choosing our own way to express our joy. The only way to fulfill our chiyuv of "Chanukah" is by fulfilling hadlokas neros Chanukah!

The Ba'alei Hakabbalah explain that the power of Chanukah lies in the Torah sheb'al Peh. The Torah sheb'al Peh directs us how to enrich our fulfillment of the mitzvos and enables us to fill our lives with the light represented by the neros Chanukah. Yehi ratzon that we all merit to illuminate our lives with the radiance of Torah through our ahavas
haTorah, and through that Torah merit to see as in the days of the Chashmonaim , the rededication of the Beis HaMikdash in Yerushalayim.