Revelation 21:15 in the King James Version
And he that talked with me had a golden reed to measure the city, and the gates thereof, and the wall thereof.
Context
14 The wall of the city had twelve foundations, and on them twelve names of the twelve Apostles of the Lamb.
15 He who spoke with me had for a measure a golden reed to measure the city, its gates, and its walls.
16 The city is square. Its length is as great as its width. He measured the city with the reed: twelve thousand twelve stadia. Its length, width, and height are equal.