Leviticus 23:26-32

The LORD spoke to Moses, saying, “Also the tenth day of this seventh month is the Day of Atonement; it shall be a holy convocation for you, and you shall humble yourselves [by fasting] and present an offering by fire to the LORD. You shall not do any work on this same day, for it is the Day of Atonement, to make atonement on your behalf before the LORD your God. If there is any person who will not humble himself on this same day, he shall be cut off from his people [excluding him from the atonement made for them]. If there is any person who does any work on this same day, I will destroy that person from among his people. You shall do no work at all [on that day]. It is a permanent statute throughout your generations wherever you may be. It is to be to you a Sabbath of complete rest, and you shall humble yourselves. On the ninth day of the month at evening, from evening to evening you shall keep your Sabbath.”