Kapłańska 23:32 Halacha: Mishneh Torah, Rest, The Sabbath Epistle, Mishneh Torah, Positive Mitzvot & Sefer HaChinukh

There is a positive commandment to rest from labor on the tenth of the seventh month [Tishrei], as it is stated (Leviticus 23:32), "It shall be a Shabbat of rest for you." And anyone who does labor on it has negated a positive commandment and violated a negative commandment, as it is stated (Numbers 29:7), "And on the tenth. etc. you shall not do any labor." And what is he liable for doing labor on this day? If he did it willingly and volitionally, he is liable for excision. But if he did it inadvertently, he is liable a fixed sin-offering .

We have also learned from the oral tradition that it is forbidden to wash [one's body], anoint oneself, wear shoes, or have sexual relations on it. And it is a commandment to refrain from all of these [activities] in the same manner that one refrains from eating and drinking, as it is stated (Leviticus 16:31), "a Sabbath of rest" — "a Sabbath" for the matter of (eating); "rest" for these [other] matters. But one is only liable for excision or an offering for eating and drinking. However, if one washed, anointed, put on shoes, or had sexual relations, he is given (rabbinic) lashes for rebellion.

In the same manner that resting from labor applies during the day and at night, so too refraining for the other prohibitions of affliction applies during the day and at night. One must add from the profane to the holy by starting the Day of Atonement while it is still day and ending it later than nightfall, as it says "and you shall afflict your souls on the 9th of the month, in the evening." Meaning to say, begin to fast and afflict oneself from the evening of the 9th which is close to the 10th [i.e. the evening before the 10th]. So too, at its departure, delay in his affliction a short while in the night of the 11th that is close to the 10th [i.e. the night after the 10th], as it says "from evening to evening, you shall rest your Sabbath."