Contributed by: R. Ezra Mizrahi
Most Jewish holidays, if longer than one or two days, last seven days. Why is Hanukah eight days?
Why did the miracle of "Pach HaShemen" last for 8 days?
Once the Kohanim entered into Bet Hamiqdash, they only found one-day supply of oil for the Menorah. This means that they had enough oil to fill all seven cups of the Menorah for only one day. As you know, the Menorah in the Bet Hamiqdash had seven cups and was completely lit every day by the Kohanim.
During that first day, the Kohanim realized that they did not have enough oil for the next day. They sent people to a city where olives were still growing at this time of the year. The city was three days away. For three days they traveled there, and for three days they traveled back to Yerushalayim. It then took one day to process the olives into pure olive oil to be used for the Menorah.
From the time the Kohanim sent the dispatch until they had ready oil took eight days. During that time the oil they found lasted. This is why the length of the holiday is eight days, and why the miracle did not continue for more time, or end sooner.