Leviticus 23:27-32

On exactly the tenth day of this seventh month is the day of atonement; it shall be a holy convocation for you, and you shall afflict your souls and present an offering by fire to Yahweh. You shall not do any work on this same day, for it is a day of atonement, to make atonement on your behalf before Yahweh your Elohim. If there is any person who will not afflict himself on this same day, he shall be cut off from his people. As for any person who does any work on this same day, that person I will destroy from among his people. You shall do no work at all. It is to be a perpetual statute throughout your generations in all your dwelling places. It is to be a Sabbath of complete rest to you, and you shall afflict your souls; on the ninth of the month at evening, from evening until evening you shall keep your Sabbath.