Exodus 29:35-39

“So you shall do for Aaron and for his sons, according to all that I have commanded you; you shall ordain them for seven days.

Each day you shall offer a bull as a sin offering for atonement, and you shall purify the altar when you make atonement for it, and you shall anoint it to consecrate it.

For seven days you shall make atonement for the altar and consecrate it; then the altar shall be most holy, and whatever touches the altar shall be holy.

“Now this is what you shall offer on the altar: two one-year-old lambs each day, continuously.

The one lamb you shall offer in the morning, and the other lamb you shall offer at twilight;