Revelation 21:9-17 ESV
Then came one of the seven angels who had the seven bowls full of the seven last plagues and spoke to me, saying, “Come, I will show you the Bride, the wife of the Lamb.” And he carried me away in the Spirit to a great, high mountain, and showed me the holy city Jerusalem coming down out of heaven from God, having the glory of God, its radiance like a most rare jewel, like a jasper, clear as crystal. It had a great, high wall, with twelve gates, and at the gates twelve angels, and on the gates the names of the twelve tribes of the sons of Israel were inscribed— on the east three gates, on the north three gates, on the south three gates, and on the west three gates. And the wall of the city had twelve foundations, and on them were the twelve names of the twelve apostles of the Lamb.
And the one who spoke with me had a measuring rod of gold to measure the city and its gates and walls. 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. He also measured its wall, 144 cubits by human measurement, which is also an angel’s measurement.
ESV: English Standard Version 2016