Q. Why do the Books of Maccabees do not mention the jar of oil?
A. The story is neither in Maccabees nor Josephus. The first time we find it is centuries later in the Talmud (Shab. 21b), where the focus changes from the military victory to the Divine miracle. Obviously the rabbis knew of the Maccabean wars, but what they disapproved of was the emphasis on military might and political power.
With the perspective of history they saw that the spiritual dimension was lost after the victory when the Maccabees became susceptible to corruption and the other failings that often characterise politicians. History therefore needed to recognise that national independence was not the only important achievement: the crucial victory was the survival of Judaism.
There is a Chassidic saying, “Hallel is said on Chanukah and not on Purim because on Purim the body of the Jew was saved and on Chanukah it was his soul”. One can go further and say that without the story of the jar of oil Chanukah would have risked becoming a Purimspiel.