Revelation 21:16

16 The city was laid out like a square, as long as it was wide. He measured the city with the rod and found it to be 12,000 stadiaa in length, and as wide and high as it is long.

Read Revelation 21:16 Using Other Translations

And the city lieth foursquare, and the length is as large as the breadth: and he measured the city with the reed, twelve thousand furlongs. The length and the breadth and the height of it are equal.
The city lies foursquare, its length the same as its width. And he measured the city with his rod, 12,000 stadia. Its length and width and height are equal.
When he measured it, he found it was a square, as wide as it was long. In fact, its length and width and height were each 1,400 miles.