Leviticus 16:29-31 (KJV)
29 And this shall be a statute for ever unto you: that in the seventh month, on the tenth day of the month, ye shall afflict your souls, and do no work at all, whether it be one of your own country, or a stranger that sojourneth among you:
30 For on that day shall the priest make an atonement for you, to cleanse you, that ye may be clean from all your sins before the Lord.
31 It shall be a sabbath of rest unto you, and ye shall afflict your souls, by a statute for ever.
Leviticus 23:27-32 (KJV)
27 Also on the tenth day of this seventh month there shall be a day of atonement: it shall be an holy convocation unto you; and ye shall afflict your souls, and offer an offering made by fire unto the Lord.
28 And ye shall do no work in that same day: for it is a day of atonement, to make an atonement for you before the Lord your God.
29 For whatsoever soul it be that shall not be afflicted in that same day, he shall be cut off from among his people.
30 And whatsoever soul it be that doeth any work in that same day, the same soul will I destroy from among his people.
31 Ye shall do no manner of work: it shall be a statute for ever throughout your generations in all your dwellings.
32 It shall be unto you a sabbath of rest, and ye shall afflict your souls: in the ninth day of the month at even, from even unto even, shall ye celebrate your sabbath.