During the Second Temple period, Hannukah was a festival of independence and victory. This is how the historians of the time describe it, and so it is eternalized by our Sages in the prayer service and the Grace After Meals:
“You, in Your great mercy, stood with them in their time of trouble: You fought their fight, judged their judgment, avenged their vengeance; You gave the mighty over into the hands of the weak; the many into the hands of the few; the defiled into the hands of the pure; the wicked into the hands of the righteous; the evil ones into the hands of those engaged in Your Torah. And You made Your name great and holy in Your world, and for Your nation, Israel, You performed great salvation and liberation on this day. And then Your children came to Your holy house, cleared the Sanctuary, purified Your Temple, and kindled lights in Your holy courtyards, and they established these eight days of Hannukah for thanks and praise to Your great name.”
There is no mention here of the miracle of the tiny cruse of oil that sufficed for eight days. The Temple was rededicated; the victory of the Hasmoneans over the Greeks found expression in the holy Temple service and national liberation. Just as one pays no attention to the light of a candle when the sun is shining, so the national focus cannot turn to specific miracles such as that of the cruse of oil.
Later, the Temple was destroyed, the Temple service abolished, and Israel exiled from the land. Rome and Byzantium reigned. A difficult question faced the Sages of the exile: How should the day of independence be commemorated after independence has been lost? This is the question posed in the Gemara, in Massekhet Shabbat 21b: “What is Hannukah?” I.e., what is the significance of Hannukah now, for us, in our orphaned generation.
The Sages respond: Hannukah is the miracle of the cruse of oil. Their intention seems to be that the crux of the festival does not celebrate the physical victory and the salvation of the Hasmoneans. They were kohanim (and therefore forbidden to rule), and they also conducted a civil war; therefore their victory did not last and the Temple was destroyed because of causeless hatred. (Ramban, Bereishit 49:1)
If we wish to study the message that the Sages bequeathed to all generations concerning Hannukah, we cannot ignore the fact that the Gemara is quite severe in its treatment of the Hasmonean dynasty, and that it ignores completely the aspects of victory and independence related to the festival. Our Sages wanted to teach us that our power to vanquish the darkness is dependent on candles, on light; not only on the sword. Many nations and religions believe that the darkness and evil in the world can be defeated by means of mighty weapons, nuclear missiles, etc. Hannukah comes to teach us the obligation of “publicizing the miracle”: the obligation of kindling light, without which no physical power will overcome darkness. And the obligation of kindling extends to the time when “the last gentile leaves the marketplace…” (Shabbat ibid.)