Leviticus 23:23-28
(Rosh Hashanah/Yom Kippur)
And the Lord spoke to Moses, saying, Speak to the children of Israel, saying: In the seventh month, on the first of the month, it shall be a Sabbath for you, a remembrance of [Israel through] the shofar blast a holy occasion. You shall not perform any work of labor, and you shall offer up a fire offering to the Lord.
And the Lord spoke to Moses, saying: But on the tenth of this seventh month, it is a day of atonement, it shall be a holy occasion for you; you shall afflict yourselves, and you shall offer up a fire offering to the Lord. You shall not perform any work on that very day, for it is a day of atonement, for you to gain atonement before the Lord, your God.