Rav Yoel Bin-Nun (in a Shiur he delivered at TABC) pointed out that the holiday of Chanukah was actually a holiday before it was even rabbinically instituted. The Gemara (Avodah Zarah 8a) vividly describes the first day of Adam HaRishon, from his creation in the month of Tishrei (Rosh Hashanah to be exact) to the sin of the Eitz HaDaat. Hashem told him that from the moment of that sin on, he was destined to die. As the weeks progressed, the days kept getting much shorter and the nights became ever-longer. Eventually, Adam believed that his death was to take place in the form of complete darkness with no light, thus reversing the process of creation and returning the world to “Tohu VaVohu.” On the 17th of the month of Kislev, one of the shortest weeks of the year, Adam HaRishon decided to fast and pray for eight days to address this concern. On the eighth day of fasting, the 25th of Kislev and the winter equinox, Adam HaRishon realized something remarkable: the days began to lengthen and the nights to shorten. Adam then understood the ideas of the solstice and equinox. The following year, Adam HaRishon decided to make the eight days of his fast and the eight days after it into a holiday. This was not only a festival of the Jews, but of all mankind. Since it was the darkest period of the year, people lit lights as part of the holiday. Many years later, the Jews reinstituted this holiday to commemorate their national miracle of (extra) light. In this sense, Chanukah is a “festival of lights” from the historical perspective.
Another aspect of this property of Chanukah emerges from Al HaNissim. It seems rather puzzling that we say in this Tefillah, “VeHidliku Neirot BeChatzrot Kodshecha,” “they lit lights in the courtyard of the Beit HaMikdash.” The menorah was not in fact situated in the “courtyard”; it was inside of the Kodesh, an inner section of the Beit HaMikdash! What do we mean by this phrase?
Rav Yoel noted that one of the few Mishnayot which discuss Chanukah states that Bikkurim, the first fruits which must be brought to the Beit Hamikdash, may be brought from Shavuot until Sukkot. They may also be brought between Sukkot to Chanukah (but no later). The reason for having extended the time until Chanukah is that the olives are ripe (and thus ready to be picked) at this time of the year, in Kislev. Therefore, all of Klal Yisrael were bringing olives to the Beit HaMikdash in the month of Kislev; the olive-bringing season made up the tail end of the Bikkurim season. There was then a surplus of oil for the Beit HaMikdash, to the point where it would be impossible to use it all just for the Menorah. Consequently, they took the oil and lit candles all over Yerushalayim, even in the courtyard of the Beit HaMikdash. After the miracle of Chanukah occurred, the lighting of candles in the Chatzer of the Beit HaMikdash was once again practiced. Thus, Chanukah represented a restoration of the lighting practices of old – truly a religious “festival of lights.”