Ezekiel 43:16-19

It is square, twenty-one feet long and twenty-one feet wide. The upper ledge is also square, twenty-four and one-half feet long and twenty-four and one-half feet wide. The rim around the altar is ten and one-half inches wide, and its gutter is twenty-one inches wide all around. Its steps are on the east side.” Then the man said to me, “Human, this is what the Lord GOD says: These are the rules for the altar. When it is built, use these rules to offer burnt offerings and to sprinkle blood on it. You must give a young bull as a sin offering to the priests, the Levites who are from the family of Zadok and who come near me to serve me, says the Lord GOD.