Chanuka is unique in that it is a Yom Tov that was completely instituted by the Chachamim, from beginning to end, with no source in the Torah. (Purim falls under the same category.)  Our Chachamim have the authority to add Rabbinic ordinances, which we are obligated to adhere to. The Gemara in Shabbos which introduces the Yom Tov of Chanuka discusses this obligation, especially in relation to the Mitzvah of Hadlakas Ner Chanukah.  The Amoraim offer two sources for the obligation to observe Mitzvos M'Derabanan - one source being the Lav of Lo Sasur, and the other source being the pasuk of Zekeinecha V’yomru Lach.  These two sources have different halachic ramifications when applied to the fulfillment of Rabbinic ordinances.

Among the questions discussed:

• If there is an obligation Min Hatorah to adhere to the Chachamim, then how do ever have a concept of Safek Drabbanan L’kula?
• On Chanuka, did the Chachamim just add new Mitzvos, or did they also create a new Yom Tov?
• Why does the Gemara address the question of listening to Chachamim specifically when discussing the mitzvah of Ner Chanuka, and not by other Mitzvos D’rabanan, such as Eiruvin, Netilas Yadayim, Megillah, Hallel, etc.?
• Is the obligation to listen to our Chachamim a Mitzvas Aseh or Lo Sa'aseh?
• Assuming that this obligation stems from a Lo Sa'aseh, can we conclude that women are obligated to perform all Mitzvos D'rabanan (including Ner Chanuka), as they are obligated to observe all Lavin?