Charles Ellicott Commentary Isaiah 21:6

"For thus hath the Lord said unto me, Go, set a watchman: let him declare what he seeth:" — Isaiah 21:6 (ASV)

Go, set a watchman ... —The prophet is, as it were, placed in vision on a lofty watchtower, and reports what meets his gaze, or that of the watchman with whom he identifies himself (Ezekiel 33:7). (Compare to the striking parallel of Habakkuk 2:1-2.)