|The golden rule.|
The man with the golden reed described in Revelation 21:15 is the geometer assigned to settle the Jerusalem boundary dispute.
Behold, a man with a measuring line in his hand. (Zechariah 2:1) "NKJV"
Measuring line: standard
A man with a measuring line: the geometer
The measuring line in the hand of the geometer was described as a golden reed because the new Jerusalem (the Axis Mundi) is a golden city.
He: the geometer
Golden reed: the measuring line
The measuring line or golden reed is the standard.
The Spirit of the shall lift up a standard against him. (Isaiah 59:19) "KJV"
The new Jerusalem is about the golden rule which says,
Do for others what you want them to do for you: this is the meaning of the Law of Moses and of the teachings of the prophets. (Matthew 7:12) "GNT"
The city: the new Jerusalem (the cosmos)
The dimension of the new Jerusalem is described as follows:
The city is laid out as a square; its length is as great as its breadth. (Revelation 21:16) "NKJV"
And the three dimensional structure of the new Jerusalem is described as follows:
Its length, breadth, and height are equal. (Revelation 21:16) "NKJV"
A geometer was appointed to measure the new Jerusalem and settle the Jerusalem boundary dispute because the holy city is geometric: Revelation 21:16 portrays the city as a square and a cube.
The prophet Zechariah had the following conversation with the geometer while he (the geometer) was on his way to settle the Jerusalem boundary dispute once and for all,
And he said to me, “To measure Jerusalem, to see what is its width and what is its length.” (Zechariah 2:2) "NKJV"
The measurement obtained by the geometer was the measurement of only one stone: the jasper stone. The stones constituting the wall of the holy city are people of every tribe, race, nation and language. This means that the measurement obtained by the geometer is a human being: Jesus.
Jesus has been magnified, and the new Jerusalem is a network of people. The network is the constantly expanding space-time continuum. Therefore the geometer can't possibly arrive at an accurate measurement of a city whose boundaries are constantly changing.