The Eight-Day Miracle of Hanukkah

Based on the provided sources, traditionally Hanukkah is celebrated for eight days, not ten. The holiday was established in memory of the miracle when, despite having oil for only one day, the lamp in the Temple burned for eight consecutive days. In particular, the event is described as follows:

"Thus it is recounted in the First Book of Maccabees (chap. 4): 'And they consecrated the altar on the very same day when it had been defiled by the idolaters… And they celebrated the dedication of the altar for eight days.' The historian Josephus called Hanukkah the 'Festival of Lights' (hag orim), because salvation came to the people of Israel like a suddenly reappearing light. We remember Judah Maccabee, his brave brothers, and their renowned father, the wise and courageous Mattathias Hasmoneus."
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Also detailed is the miraculous incident with the oil:

"The Jews found a priest-sealed jar containing enough oil for one day. The priests decided to pour the oil into the menorah, and a miracle occurred: the lamp burned throughout the entire night without going out. On the next day it too burned, as well as on the third, the fourth… And on the eighth day the flame did not go out. Therefore, during the Hanukkah celebration, a hanukkiah with 9 candles is lit, not 7 as in a regular menorah."
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Both excerpts confirm that the primary event, which initiated the tradition of the festival, is connected with the eight-day miracle. Thus, the information from the sources unequivocally indicates the eight-day nature of the holiday, leaving no reason to believe that Hanukkah lasts ten days.

Supporting citation(s):
"Thus it is recounted in the First Book of Maccabees (chap. 4): 'And they consecrated the altar on the very same day when it had been defiled by the idolaters… And they celebrated the dedication of the altar for eight days'..." (source: link txt)
"The Jews found a priest-sealed jar containing enough oil for one day. The priests decided to pour the oil into the menorah, and a miracle occurred: the lamp burned throughout the night without going out. On the next day it too burned, as well as on the third, the fourth… And on the eighth day the flame did not go out..." (source: link txt)

The Eight-Day Miracle of Hanukkah