Why is Chanukah an eight-day holiday?

Hi,


"Although the miracle [of the oil] lasted only for seven days, since there was already enough oil for one day, still, only one-eighth of the oil lit each night and so the miracle occurred even on the first night.

"Others have written that [it is an eight day holiday because] the enemy had prevented the mitzvah of circumcision, which happens at eight days.

"Others have written that it is because this [first day] was the date when they dedicated the Beit haMikdash for the services which had been halted by wicked Antiochus.

"In truth, a midrash says that the work of the mishkan [in the desert] was concluded on the 25th of Kislev, and they did not dedicate it until the first of Nisan, the time when our ancestors were born. HaShem made it up to Kislev in the days of Matityahu. Therefore, they modeled Chanukah on the dedication of the mishkan, which incorporated a seven-day dedication period and then, on the eighth day, Aharon and his sons completed the inauguration of the work of the mishkan, as is explained in the Torah. King Solomon also dedicated the Beit haMikdash in this way, as is recorded in Divrei haYamim II 7:8-9... To remember this, they named the holiday 'Chanukah [dedication]', as in the dedication of the mizbeiach [altar] and the dedication of the beit hamikdash. There is also a hint in this to the 25th - 'חנו כה - They camped on 25.'

"Another reason is explained in Sefer Chashmonai: Because of the decrees, they could not bring korbanot on the previous Succot and Shmini Atzeret. To commemorate this, they created Chanukah for eight days. Then, when they were shown from heaven the miracle of the kindling, this showed that Gd agreed with their decision to make it eight days."

(R' Yechiel Michel Epstein, Aruch haShulchan Orach Chaim 670:4-5)

Chag sameach,
Mordechai