After 7 years of fighting, during which Judas won a number of battles over the Syrian armies, he returned with his followers to Jerusalem, determined to cleanse and rededicate the Temple which had been desecrated by Antichus. When it came time to light the Holy Lights they found just one jar of oil, enough to light the lamp for only one day. It would take 8 days to prepare fresh consecrated oil. Miraculously, the one jar of oil burned for 8 days and 8 nights.
Each night of the festival, the family gathers around the menorah, a special candelabrum that holds 8 candles. On the first night the head of the family uses a helper candle challed a shamos to light one candle; on the second night two candles are lit, and so on, until all eight candles are lit on the 8th night.