The first conclusion resulting from the angel’s measuring work is that the city was “foursquare.” The word translated as “foursquare” could refer to a rectangle, as the word literally means four [right] angles.
So John adds the additional words, “its length the same as its width,” to make unambiguously clear that this city is in fact a square. Symbolism is significant in the book of Revelation; a square symbolizes harmony, perfection. Moses’ tabernacle contained numerous squares, including the Most Holy Place, the altar for burnt offerings (Exodus 27:1), the altar of incense (Exodus 30:2) and the breastpiece of judgment (Exodus 28:15). The Most Holy Place in Solomon’s temple was also square (2 Chronicles 3:8), as was its altars (2 Chronicles 4:1); see also Ezekiel 41:4, Ezekiel 41:22; Ezekiel 43:16. Each of these squares communicated the presence of harmony in the relation between God and man, where nothing is crooked or out of place. So John (and the churches over the centuries) learn that the relation between “the wife” and “the Lamb” will be perfectly harmonious when all things are made new (Revelation 21:5) and there’s no more mourning nor crying nor pain anymore (Revelation 21:4). The renewing work of the Holy Spirit in today’s church ensures that the church may taste the beginnings of this harmony.
16 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.