Exodus 29:35-37

35“This is how you will ordain Aaron and his sons to their offices, just as I have commanded you. The ordination ceremony will go on for seven days.

36Each day you must sacrifice a young bull as a sin offering to purify them, making them right with the Lord. Afterward, cleanse the altar by purifying it; make it holy by anointing it with oil.

37Purify the altar, and consecrate it every day for seven days. After that, the altar will be absolutely holy, and whatever touches it will become holy.