Revelation 21:16

And the city lieth four square
To the four corners of the world, from whence its inhabitants come, and denotes the regularity, uniformity, perfection, and immovableness of it.

And the length is as large as the breadth;
this church state will be all of a piece, perfect, entire, and wanting nothing.

And he measured the city with the reed, twelve thousand furlongs;
or fifteen hundred miles; a monstrously large city indeed! such an one as never was upon earth; see ( Ezekiel 48:35 ) and which shows, that this is not to be understood literally, but mystically; and intends the capaciousness of it, here being room enough for all the twelve tribes of Israel; that is, for all the elect of God; for as in Christ's Father's house, so in this kingdom state of his, there will be many mansions, or dwelling places, enough for all his people. This city will hold them all. The Jews ^F8 say of Jerusalem, that in time to come it shall be so enlarged, as to reach to the gates of Damascus, yea, to the throne of glory.

The length, and the breadth, and the height of it are equal.
A perfectly uniform state! according to the Ethiopic version, it is in length twelve thousand furlongs, and every measure equal, so that it is so many furlongs in length, breadth, and height.