Leviticus 23:27-28

“The Day of Cleansing will be on the tenth day of the seventh month. There will be a holy meeting, and you will deny yourselves and bring an offering made by fire to the LORD. Do not do any work on that day, because it is the Day of Cleansing. On that day the priests will go before the LORD and perform the acts to make you clean from sin so you will belong to the LORD.