Leviticus 4:6-7

6He is to dip his finger into the blood and sprinkle some of it seven times before the Lord, in front of the curtain of the sanctuary.

7The priest shall then put some of the blood on the horns of the altar of fragrant incense that is before the Lord in the tent of meeting. The rest of the bull’s blood he shall pour out at the base of the altar of burnt offering at the entrance to the tent of meeting.