Exodus 27:2

27:2 You are to make its four horns on its four corners; its horns will be part of it, and you are to overlay it with bronze.

Leviticus 4:7

4:7 The priest must put some of the blood on the horns of the altar of fragrant incense that is before the Lord in the Meeting Tent, and all the rest of the bull’s blood he must pour out at the base of the altar of burnt offering that is at the entrance of the Meeting Tent.

Leviticus 4:18

4:18 He must put some of the blood on the horns of the altar which is before the Lord in the Meeting Tent, and all the rest of the blood he must pour out at the base of the altar of burnt offering that is at the entrance of the Meeting Tent.

Leviticus 4:25

4:25 Then the priest must take some of the blood of the sin offering with his finger and put it on the horns of the altar of burnt offering, and he must pour out the rest of its blood at the base of the altar of burnt offering.