Ezekiel 45:18-20

Thus says ADONAI Elohim: “In the first month, in the first day of the month, take a young bull without blemish and purify the Sanctuary. The kohen will take some of the blood of the sin offering and put it upon the doorposts of the House and upon the four corners of the ledge of the altar and upon the posts of the gate of the inner court. So you will do on the seventh day of the month for everyone who sins unintentionally or through ignorance. So you will make atonement for the House.