This week’s Parashah, Parashat Emor, contains the source for Yom Kippur. The Pasuk commands “VeInitem Et Nafshotechem BeTish’ah LaChodesh BaErev,” “You shall afflict your souls, in the ninth day of the month in the evening” (VaYikra 23:32). However, this Pasuk seems somewhat strange: if the Jewish day begins at night, why does the Pasuk not read “In the tenth day of the month in the evening,” if Yom Kippur begins on the night of the tenth of Tishrei, and not the ninth?
In order to deal with this issue, we first need to analyze the Gemara in Berachot (8b). The Gemara states that one who eats on Erev Yom Kippur is like the one who fasts of Yom Kippur itself. Why should eating on Erev Yom Kippur be equal to fasting on Yom Kippur? The Noam Elimelech suggests that on Erev Yom Kippur, when we are about to enter the holiest and most serious day of the year, the stress and anticipation makes it extremely difficult for us to bring ourselves to eat, and is almost as much of a struggle as fasting on Yom Kippur. Nonetheless, we are commanded to eat on that day, and thus must find a way to bring ourselves to eat.
The Chachamim rule that Vidui must be recited at Minchah on Erev Yom Kippur. Vidui, a confession of sins, is basically a summary of the entire Yom Kippur service. Why do we start the atonement process before the Day of Atonement begins? The Gerer Rebbe explains that if, according to the Gemara, eating on Erev Yom Kippur is like fasting on Yom Kippur, and eating on Erev Yom Kippur is in fact a struggle worthy of recognition, as explained above, there is no question as to why we say Vidui at Mincha, as Erev Yom Kippur carries great significance as a quasi-Yom Kippur. Thus, it is fitting that Erev Yom Kippur should be endowed with some of Yom Kippur’s Mitzvot.
With all this in mind, we understand that when the Torah states, “In the ninth day of the month in the evening,” it is not referring to the night of Yom Kippur, but rather to the evening beforehand, when we already begin the process of Teshuvah by overcoming the greatest challenge and forcing ourselves to eat.