Numbers 15:25, 28

Then the priest shall make atonement for all the congregation of the sons of Israel, and they will be forgiven; for it was an error, and they have brought their offering, an offering by fire to the LORD, and their sin offering before the LORD, for their error.

The priest shall make atonement before the LORD for the person who goes astray when he sins unintentionally, making atonement for him that he may be forgiven.