Charles Ellicott Commentary Revelation 21:16

"And the city lieth foursquare, and the length thereof is as great as the breadth: and he measured the city with the reed, twelve thousand furlongs: the length and the breadth and the height thereof are equal." — Revelation 21:16 (ASV)

And the city lieth foursquare . . .—The city is foursquare because its length and breadth are equal; but it is added that its height is also equal to the length and breadth. Thus, the city presents the symbol of perfect symmetry; this is all that is needed.

Many interpreters are nervously anxious about the monstrous appearance of a city whose walls measured three thousand stadia (the word rendered “furlongs” is properly stadia); but there is no need to be nervous about the symbols. The city is not designed to be represented by painting to the eye, any more than the vision of Revelation 4 or the vision of Ezekiel (Ezekiel 1): the attempt to do so only ends in the production of grotesque and profane pictures.

It is not necessary, however, in this case to suppose the actual wall to have been 3,000 stadia in height. The city is placed on a hill, the foundations are upon the holy hill, and the deep, strong mountain foundations may be included in the measurement.

The main thought, however, is to realize the harmony and proportion of that community, in which broad and low and high will meet, and in which no truth will be exaggerated or distorted; in which no disproportioned adjustments will mar its social order; and in which all those who are built in as living stones will be measured, not by the false estimates of worldly thoughts , but by the golden reed of the sanctuary.