991. Tosefes Yom Kippur

Shvisas Asor 1:6

Just as the obligation to refrain from acts of labor on Yom Kippur applies both by day and by night, the obligation to refrain from the other proscribed activities likewise applies both by day and by night. One is required to add time from the secular to the holy upon the holiday’s arrival and departure as per Leviticus 23:32, “You shall afflict yourselves on the ninth of the month in the evening.” Yom Kippur is 10 Tishrei, so the implication is that one must begin fasting and afflicting himself on the afternoon of 9 Tishrei. The same is true of Yom Kippur’s departure: one should extend his affliction a little bit into the evening of 11 Tishrei, as the verse continues, “From evening to evening, you shall observe this day of abstention.”

Shvisas Asor 1:7

If women continue eating and drinking until nightfall on 10 Tishrei, unaware of the obligation to add time from the weekday to Yom Kippur, they should not be reprimanded. This is because we are concerned that, once aware of the obligation, they may continue eating, which would then be a willful violation. It is simply not possible to police everybody’s actions, so the lesser evil is to leave the situation alone so that they violate this obligation unintentionally rather than intentionally. The same holds true in comparable situations.