Ezekiel 43:12-13

This is the law of the temple: The whole area surrounding the mountaintop is most holy. Behold, this is the law of the temple. “These are the measurements of the altar in cubits (the cubit is one cubit and a handbreadth): the base one cubit high and one cubit wide, with a rim all around its edge of one span. This is the height of the altar