Q. Is there a mitzva for women to eat on Erev Yom Kippur as men do, or is it a 'Time Depending Mitzva' and therefore women are exempt. They should just eat for the purpose of being able to fast?
Does the mitzva of eating begin on the night of the ninth or is it only on the day?
A. Mishna Berura (604:1) rules quoting Poskim that eating during Erev Yom Kippur is a Biblical mitzva.
Teshuvos R'A Eiger (16) deals with this question as do other Poskim (Hago'os Chochmas Shlomo ibid., Ksav Sofer 112, Minchas Chinich 313: 16, and others). Most maintain that women are obliged as men are, since they are obliged in the correlated and depending mitzva of fasting in Yom Kippur.
Some Poskim maintain that the mitzva of eating starts on the night before Erev Yom Kippur, when that day begins. (Shloh quoted by Magen Avrohom (604:1) and Eishel Avrohom).
However many Poskim disagree and maintain it begins only in the morning. (Biur Hagra, Yad Efraim, Piskei Teshuvos ibid. and others). Horav Shlomo Miller's Shlit'a opinion is similar.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a
Important Numbers
