That is that He commanded us to fast on the tenth day of Tishrei. And that is His, may He be exalted, saying, "afflict your souls" (Leviticus 16:29). And the explanation appears in the Sifra (Sifra, Acharei Mot, Chapter 7:3), "'Afflict' - affliction that destroys a soul. And what is that? [Abstention from] eating and drinking." And the tradition (Yoma 73a) likewise came [to teach] that it is forbidden for bathing, anointing, wearing shoes and sexual relations. And the resting is designated for all of these actions by His saying, "It is a Shabbat of Shabbaton, and you shall afflict your souls" (Leviticus 16:31): It is as if He said that the obligation is the specific resting from work and the specific resting from nourishment for the body and its preservation. And He hence said, "Shabbaton." And the language of the Sifra (Sifra, Acharei Mot, Chapter 8:3) is, "From where [do we know] that [...] bathing [and] anointment [...] are forbidden on Yom Kippur? [Hence] we learn to say, 'It is a Shabbat of Shabbaton.'" That is to say that the resting be from all of these things until he arrives at affliction. (See Parashat Acharei Mot; Mishneh Torah, Rest on a Holiday 1.)

And this shall be a statute for ever to you: that in the seventh month, on the tenth day of the month, you shall afflict your souls, and do no work at all, the home born or the stranger that sojourns among you: for on that day will he forgive you, to cleanse you, that you may be clean from all your sins before the Lord. It shall be a sabbath of solemn rest to you, and you shall afflict your souls, by a statute forever.

There is another positive commandment on Yom Kippur, to refrain from eating and drinking, as [Leviticus 16:29] states: "You shall afflict your souls." According to the Oral Tradition, it has been taught: What is meant by afflicting one's soul? Fasting.Whoever fasts on this day fulfills a positive commandment. Whoever eats or drinks on this day negates the observance of [this] positive commandment and violates a negative commandment, as [ibid. 23:29] states, "Any soul that does not afflict itself will be cut off." Since the Torah punishes a person who does not fast with karet, we can derive from this that we are forbidden to eat and drink on this day.A person who eats or drinks inadvertently on this day is liable to bring a sin offering of a fixed nature.

Similarly, according to the Oral Tradition, it has been taught that it is forbidden to wash, anoint oneself, wear shoes, or engage in sexual relations on this day. It is a mitzvah to refrain from these activities in the same way one refrains from eating and drinking.This is derived from [the exegesis of the expression,] "A Sabbath of Sabbaths." "A Sabbath" implies refraining from eating; "of Sabbaths," refraining from these activities.One is liable, however, for karet or a sin offering only for eating and drinking. If one washes, anoints oneself, wears shoes, or engages in sexual relations, one receives stripes for rebelliousness.

Just as [the obligation to] refrain from work applies both during the day and at night, so too, [the obligation to] refrain from [these activities and thus to] afflict oneself applies both during the day and at night.It is obligatory to add [time] from the mundane to the sacred at both the entrance and departure of the holiday, as [implied by ibid. 23:32]: "And you shall afflict your souls on the ninth of the month in the evening." [Since the date of the fast is the tenth,] the intent is [obviously] that one begin fasting and afflicting oneself in the afternoon of the ninth, which directly precedes the tenth.Similarly, at the departure [of the holiday], one should prolong the affliction slightly, [entering] the night of the eleventh, which follows the tenth, as [implied by ibid.]: "From evening to evening, you shall keep this day of refraining."

On Yom Kippur, a person is liable for eating [an amount of] food that is fit for humans to eat and is equivalent to the size of a large ripe date - i.e., slightly less than the size of an egg. All foods [that one eats] are combined to produce this measure.Similarly, one who drinks a cheekful of liquid fit to be drunk by humans is liable. The size of a cheekful is [not a standard measure,] but rather dependent on the size of the cheek of every individual.What is meant by a cheekful? Enough [liquid] for a person to swish to one side of his mouth and for his cheek to appear full. For an ordinary person, this measure is less than a revi'it.All liquids [that one drinks] are combined to produce this measure. Foods and liquids are not combined in a single measure.

[The following rules apply when] a person eats a small amount, [pauses,] and eats again: If the time from when he begins eating until he concludes eating is less than the time it takes to eat an amount of bread and relish equal in size to three eggs, [the food that he eats] is included in the same measure. If not, it is not included in the same measure.[Similar rules apply when] a person drinks, [pauses,] and drinks again: If the time from when he begins drinking until he concludes drinking is less than the time it takes to drink a revi'it, [the liquid that he drinks] is included in the same measure. If not, it is not included in the same measure.

When a person who is dangerously ill asks to eat on Yom Kippur, he should be fed because of his request until he says, "It is enough," even though expert physicians say that it is unnecessary.When the sick person says that it is unnecessary for him to eat, and a physician says that it is necessary, he should be fed according to [the physician's] instructions, provided the physician is an expert.When one physician says that it is necessary [for a sick person to eat], and another physician says that it is unnecessary, the person should be fed. If several physicians say that it is necessary [for a sick person to eat], and other physicians say that it is unnecessary, [the ruling] follows the majority, or those with the most expertise. [This applies] provided the sick person does not himself say that it is necessary [for him to eat]. If, however, he makes such a statement, he should be fed.If the sick person does not say that he must [eat], the physicians were divided on the issue, they were all experts, and an equal number took each side, he should be fed.

When a pregnant woman smells food, [and is overcome by desire for it,] we should whisper in her ear that today is Yom Kippur. If this reminder is sufficient to calm her senses, it is desirable; if not, she should be fed until her desire ceases.Similarly, if a person is overcome by ravenous hunger, he should be fed until he sees clearly. He should be fed immediately, even if it necessitates giving him non-kosher meat or [meat from a] loathsome species. We do not require that he wait until permitted food becomes available.

[From the time] a child is nine or ten years old [onward], he should be trained [to fast] for several hours. What is implied? If he is used to eating two hours after daybreak, he should be fed in the third hour. If he is used [to eating] after three hours, he should be fed in the fourth. According to the child's stamina, we should add hours to his anguish.When a child is eleven years old, whether male or female, it is a Rabbinic ordinance that he complete his fast so that he be trained in [the observance of] the mitzvot.

A female who is twelve years old and one day and a male who is thirteen years old and one day, who manifest [signs of physical maturity - i.e.,] two [pubic] hairs, are considered to be adults with regard to [the observance of] all the mitzvot, and are obligated to complete their fast according to the Torah. If, however, they did not manifest [signs of physical maturity], they are still considered to be minors, and are obligated to complete their fast only by virtue of Rabbinic decree.A child who is less than nine years old should not be afflicted at all on Yom Kippur, lest this lead to danger.

It is forbidden to wash on Yom Kippur, whether using hot or cold water. One may not wash one's entire body [at one time], nor any individual limb. It is even forbidden to immerse one's small finger in water.A king and a bride may wash their faces: a bride so that she will not appear unattractive to her husband, and a king so that he will appear splendorous, as [Isaiah 33:17] states: "Your eyes shall behold the king in his splendor." Until when is a wife considered to be a "bride"? For thirty days.

When a person is soiled with filth or mud, he may wash off the dirt in an ordinary manner without reservation. [Similarly,] a woman may wash one hand in water and give a piece of bread to a child.A person who is ill may wash in an ordinary manner even though he is not dangerously ill. Similarly, all those who are obligated to immerse themselves [for the sake of ritual purity] should immerse themselves in an ordinary manner. This applies both on Tish'ah B'Av and on Yom Kippur.

It is forbidden to wear a [leather] shoe or a sandal, even on one foot. It is, however, permitted to wear a sandal made of reeds, rushes,or the like. Similarly, a person may wind cloth over his feet or the like, for his feet remain sensitive to the hardness of the ground and he feels as if he is barefoot.Although children are allowed to eat, drink, wash, and anoint themselves, they should be prevented [from wearing] shoes and sandals.

All people are allowed to wear sandals [to protect themselves] from being bitten by scorpions and the like.A woman who has just given birth may wear sandals for thirty days, lest she be chilled. The same law applies to other people who are sick, even if their illness is not dangerous.

[Just as it is forbidden to anoint] one's entire body, so too, is it forbidden to anoint a portion of one's body. [This restriction applies] both to anointment that brings one pleasure and to anointment that does not bring one pleasure.When a person is sick, however, or if he has sores on his scalp, he may anoint himself in an ordinary manner without any reservation.