Zos Chanukah, the eighth day of Chanukah, is said to be a special time for Tefillah, and according to the Bnei Yissoschar it is a time of Gmar Din for the Tefillos of the Yomim Nora’im – the High Holidays.
The Rebbe of Ruzin is quoted as saying that the Tefillos of a simple person on Zos Chanukah is comparable to the Tefillos of Tzadikim on Rosh Hashana and Yom Kippur.
On the last day of Chanukah we read the Torah portion of “Zos Chanukas HaMizbeiach” – “THIS is the dedication of the altar”.. By saying “THIS is Chanukah” we are indicating the eight day of Chanukah encapsulates the entire festival of Chanukah. Up until now, every day ushered in was one of potential. On the eighth day, the final day, all comes into actuality with ALL the lights being lit.