Albert Barnes Commentary Revelation 21:15

"And he that spake with me had for a measure a golden reed to measure the city, and the gates thereof, and the wall thereof." — Revelation 21:15 (ASV)

And he that talked with me. The angel (Revelation 21:9).

Had a golden reed to measure the city. See the notes on Revelation 11:1.

The reed, or measuring rod, here, is of gold, because all about the city is of the most rich and costly materials. The rod is thus suited to the personage who uses it, and to the occasion. Compare a similar description in Ezekiel 40:3-5; 43:16. The object of this measuring is to show that the city has proper architectural proportions.

And the gates thereof, etc. To measure every part of the city, and to ascertain its exact dimensions.