Leviticus 16:14, 19

He shall take some of the bull’s blood and sprinkle it with his finger on the east side of the mercy seat; also in front of the mercy seat he shall sprinkle some of the blood with his finger seven times.

With his finger he shall sprinkle some of the blood on the altar of burnt offering seven times and cleanse it and consecrate it from the uncleanness of the Israelites.