Yom Kippur stands as a profound moment of introspection, intertwining absolute rest with physical restraint. Its ultimate purpose is independent spiritual purification, a process that relies neither on the physical Temple nor on animal sacrifices, but rather prepares the individual mind for the immense joy of the upcoming festival of Sukkot [פירושי רד צ הופמן].
The day is declared a complete and ultimate rest. Unlike the weekly Sabbath, where the primary focus is abstaining from labor to testify to God's creation of the world, Yom Kippur introduces an additional layer. The intense emphasis on rest indicates that the cessation of activity extends to refraining from physical pleasures, fulfilled through the command to endure the physical affliction of fasting [העמק דבר, רש ר הירש]. Furthermore, a subtle distinction is made regarding the ownership of this sacred time. While the weekly Sabbath was sanctified by God from the dawn of creation and is dedicated directly to Him, the annual festivals and Yom Kippur are established and sanctified by the people of Israel and their courts. Thus, the day is affectionately attributed to the people as their own Sabbath [אבן עזרא, חזקוני, תורה תמימה].
An intriguing detail emerges regarding the date, as the instruction directs attention to the ninth day of the month, even though the fast itself occurs on the tenth. On a practical level, this guides the people to begin their fast at the very end of the ninth day. However, a deeper spiritual principle is at play. The primary approach among commentators is that anyone who eats and drinks on the ninth day is credited as if they had fasted for two consecutive days, a commandment that applies equally to men and women [פרדס יוסף, תורה תמימה].
The commentators offer several layers of meaning to explain why partaking in food is elevated to the level of fasting. Practically, it serves as physical preparation, granting a person the necessary strength to endure the upcoming trial [פרדס יוסף]. Psychologically, the sharp transition from a day of abundant feasting and pleasure to a day of complete deprivation makes the subsequent fast feel significantly more difficult. In this sense, the eating itself amplifies the affliction of the following day [תורה תמימה]. Another perspective notes that a person who eats a large meal right before the fast will remain full well into the tenth day, delaying the onset of hunger. To compensate for this delayed affliction and to encourage proper preparation, the Torah generously credits the preparatory meal as if it were an additional day of fasting [קונטרס חיבה יתירה]. Beyond these reasons lies a profound ideological message. The strict obligation to eat before fasting entirely dismantles the pagan notion of bodily self-mutilation aimed at appeasing an angry deity. It serves as definitive proof that the Jewish fast is not designed as a punishment, but rather as a refined moral and spiritual tool for achieving atonement [רש ר הירש].
The time frame for this observance, spanning from one evening to the next, establishes the fundamental structure of the Jewish calendar, where a new day always begins and ends at nightfall [תורה תמימה, אדרת אליהו, חזקוני]. Yet, the emphasis on the evening hours also introduces the crucial obligation to add from the profane to the holy. The fast and the cessation of labor do not commence precisely at sunset; instead, they must be initiated earlier in the afternoon of the ninth day, and similarly extended slightly into the night following the tenth day [שד״ל, מלבי״ם, ביאור יש״ר].
The concluding directive regarding the observance of this rest appears seemingly repetitive. However, commentators reveal that this final instruction expands far beyond Yom Kippur itself. The mandate to begin resting early, deliberately drawing time from the ordinary weekday into the sacred realm, applies universally to every period of rest observed by the Israelites, encompassing all weekly Sabbaths and festival days throughout the year [מלבי״ם, תורה תמימה, העמק דבר, אדרת אליהו].