What we should do on the ninth day of Tishre, Yom Kippur eve? TB Yoma 81

Today’s daf TB Yoma 81 teaches us two important ideas. The first is the necessity to increase the amount of sacred time of the holiday both before and after the holiday. Rav Aḥa bar Ya’akov derives this concept from the following verse.

“And you shall afflict your souls on the ninth day of the month at evening, from evening until evening, you shall rest on your Shabbat” (Leviticus 23:32). One might have thought that one should start to afflict oneself on the ninth of Tishrei; therefore, the verse states “at evening.” If the Torah had stated only “at evening,” one might have thought that the fast starts only when darkness falls; therefore, the verse states “on the ninth,” implying that one begins to fast on the ninth of Tishrei. How can these verses be reconciled? One begins to fast while it is still daytime; from here it is derived that one sanctifies and extends from the non-sacred weekday to the sacred day of Yom Kippur (תּוֹסֶפֶת יוֹם כִּיפּוּר).

“I have derived only that one must add time at the beginning of Yom Kippur. From where do I derive that one adds time at the conclusion of Yom Kippur? The verse states: “From evening until evening” (Leviticus 23:32), implying that one adds at the end as well, just as he does at the beginning. And I have derived only the mitzva of adding to Yom Kippur; from where is it derived that one must also sanctify and append time before and after Festivals (תּוֹסֶפֶת יוֹם טוֹב)? The verse states: “You shall rest” (Leviticus 23:32), to teach that this rule applies even to Festivals, on which one is commanded to rest. I have derived only that one adds an extension to Festivals; from where do I derive that one must also sanctify and append to Shabbatot (תּוֹסֶפֶת שַׁבָּת)? The verse states: “Your Shabbat” (Leviticus 23:32). How so? Every place the term: Rest [shevut] is stated, it teaches from here that one sanctifies and appends from the non-sacred weekday to the sacred.” (Sefaria.org translation)

Since the rabbis conceived that the Torah is perfect, two verses cannot come to teach the same thing for that would be redundant. Each verse must come to teach something else. What the tanna learns from the verbal analogy is unimportant for us to know right now. We are more interested in how he interprets the verse “on the ninth day of the month.”

“The Gemara asks: And the tanna who learns a verbal analogy from the words “that same day,” “that same day,” what does he do with the phrase: “On the ninth day of the month”? The Gemara answers: He requires it, in accordance with that which Ḥiyya bar Rav of Difti taught. As Ḥiyya bar Rav of Difti taught: It states: “And you shall afflict your souls on the ninth day of the month” (Leviticus 23:32). But does one afflict oneself on the ninth of Tishrei? Doesn’t one in fact afflict oneself on the tenth of Tishrei? Rather, the verse comes to tell you: Anyone who eats and drinks on the ninth of Tishrei and then fasts on the tenth, the verse ascribes him credit as though he fasted on both the ninth and the tenth. The verse alludes to this when it states that the fast is on the ninth.” (Sefaia.org translation)

In other words just as it is a mitzva to fast on the 10^th day of Tishre, Yom Kippur, it is a mitzvah to eat on the ninth day! Rashi explains very cogently why. Eating on the ninth day enables us to fulfill the mitzva of fasting on the 10^th day.