The altar hearth shall be square at its four corners, twelve cubits long and twelve cubits wide.
This relates to the altar in this mystical temple, and that is mystical too; for Christ is our altar. The Jews, after their return out of captivity, had an altar long before they had a temple, Ezr 3:3. But this was an altar in the temple. Now here we have, I. The measures of the altar, Eze 43:13.
Commenting on Ezekiel 43:13-27
And the altar shall be twelve cubits long, twelve broad,.... The length of it, from east to west, was twelve cubits; and the breadth, from north to south, was the same; so that it was a proper foursquare, as follows: Christ the altar, or the doctrine of his sacrifice and satisfaction for the sins of men, is the doctrine of the twelve apostles of Christ...
square in the four squares--square on the four sides of its squares [FAIRBAIRN].