Ezekiel 43:12-13

12This is the law of the house; Upon the top of the mountain its whole limit all around shall be most holy. Behold, this is the law of the house.

13And these are the measures of the altar after the cubits: The cubit is a cubit and an hand breadth; even the bottom shall be a cubit, and the breadth a cubit, and the border of it by its edge on every side shall be a span: and this shall be the higher place of the altar.12