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

Isaiah 21:6. For thus hath the Lord said unto me — I speak only what God hath caused me to see and hear in a vision, the particulars whereof are related in the following verses. “The Holy Spirit, to make Isaiah, and, by him, the church, most certain of this memorable event, confirms the preceding revelation by an elegant emblem, offered to the prophet in vision. This emblem exhibits to us the prophet commanded by God to set a watchman, in this verse; and, in what follows, the consequence of the execution of the command, namely, that the watchman attended accurately to the least motion of the nations against Babylon, and, after long expectation, had discovered” what is afterward related. See Vitringa. The reader will observe, that as the command to set a watchman was given to the prophet in a vision, so it was executed by him only in a vision. It signified, however, what should really be done afterward, namely, when the Medes and Persians should march to besiege and attack Babylon.

21:1-10 Babylon was a flat country, abundantly watered. The destruction of Babylon, so often prophesied of by Isaiah, was typical of the destruction of the great foe of the New Testament church, foretold in the Revelation. To the poor oppressed captives it would be welcome news; to the proud oppressors it would be grievous. Let this check vain mirth and sensual pleasures, that we know not in what heaviness the mirth may end. Here is the alarm given to Babylon, when forced by Cyrus. An ass and a camel seem to be the symbols of the Medes and Persians. Babylon's idols shall be so far from protecting her, that they shall be broken down. True believers are the corn of God's floor; hypocrites are but as chaff and straw, with which the wheat is now mixed, but from which it shall be separated. The corn of God's floor must expect to be threshed by afflictions and persecutions. God's Israel of old was afflicted. Even then God owns it is his still. In all events concerning the church, past, present, and to come, we must look to God, who has power to do any thing for his church, and grace to do every thing that is for her good.Go, set a watchman - This was said to Isaiah in the vision. He represents himself as in Babylon, and as hearing God command him to set a watchman on the watch-tower who would announce what was to come to pass. All this is designed merely to bring the manner of the destruction of the city more vividly before the eye. 6. Go, set a watchman, let him declare what he seeth—God's direction to Isaiah to set a watchman to "declare" what he sees. But as in Isa 21:10, Isaiah himself is represented as the one who "declared." Horsley makes him the "watchman," and translates, "Come, let him who standeth on the watchtower report what he seeth." Thus hath the Lord said unto me; I speak not my own fancies, but what God hath made me to see and hear in a vision; the particulars whereof are related in the following verses.

A watchman; either,

1. A prophet; such being oft so called, as Ezekiel 3:17 33:2. Or rather,

2. A military watchman. For this was now done only in a vision, which yet did foresignify what should be done really afterwards.

Let him declare, to thee in vision, to them really.

For thus hath the Lord said unto me,.... This is a confirmation of the above prophecy from the Lord himself, he showing to the prophet, in a visionary way, the ruin of Babylon, and the means and instruments of it:

go, set a watchman; not Habakkuk, as Jarchi; nor Urias, as the Septuagint; nor Jeremiah, as others; but himself, who, in a way of vision, represented a watchman on the walls of Babylon; and which was no way unsuitable to his character and office as a prophet:

let him declare what he seeth; what he sees coming at a distance, or at hand, let him faithfully and publicly make it known: these are not the words of the king of Babylon to one of his watchmen; but of the Lord of hosts to his prophet.

For thus hath the {i} Lord said to me, Go, set a watchman, let him declare what he seeth.

(i) That is, in a vision by the spirit of prophecy.