In Leviticus 23 verses 26 to 32 we read the instructions given to Moses regarding Yom Kippur (The day of atonement)
26 ADONAI said to Moshe, 27 “The tenth day of this seventh month is Yom-Kippur; you are to have a holy convocation, you are to deny yourselves, and you are to bring an offering made by fire to ADONAI. 28 You are not to do any kind of work on that day, because it is Yom-Kippur, to make atonement for you before ADONAI your God. 29 Anyone who does not deny himself on that day is to be cut off from his people; 30 and anyone who does any kind of work on that day, I will destroy from among his people. 31 You are not to do any kind of work; it is a permanent regulation through all your generations, no matter where you live. 32 It will be for you a Shabbat of complete rest, and you are to deny yourselves; you are to rest on your Shabbat from evening the ninth day of the month until the following evening.”
This is an interesting discussion about the role of the High Priest and the people of Yom Kippur.