And he shall sprinkle of the blood upon it with his finger seven times, and cleanse it, and hallow it from the uncleanness of the children of Israel.
Ezekiel 43:18-22
18
And He said unto me, "Son of man, thus saith the Lord GOD: These are the ordinances of the altar on the day when they shall make it, to offer burnt offerings thereon and to sprinkle blood thereon.
19
And thou shalt give to the priests, the Levites who are of the seed of Zadok, who approach Me to minister unto Me, saith the Lord GOD, a young bullock for a sin offering.
20
And thou shalt take of the blood thereof, and put it on the four horns of it and on the four corners of the ledge and upon the border round about; thus shalt thou cleanse and purge it.
21
Thou shalt take the bullock also of the sin offering, and he shall burn it in the appointed place of the house, outside the sanctuary.
22
And on the second day thou shalt offer a kid of the goats without blemish for a sin offering; and they shall cleanse the altar, as they cleansed it with the bullock.
Zechariah 13:1
"In that day there shall be a fountain opened to the house of David and to the inhabitants of Jerusalem, for sin and for uncleanness.