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.

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.

The prophecy is continued with the conjunction "for" (ci). The tacit link in the train of thought is this: they act thus in Babylon, because the destruction of Babylon is determined. The form in which this thought is embodied is the following: the prophet receives instruction in the vision to set a metzappeh upon the watch-tower, who was to look out and see what more took place. "For thus said the Lord to me, Go, set a spy; what he seeth, let him declare." In other cases it is the prophet himself who stands upon the watch-tower (Isaiah 21:11; Habakkuk 2:1-2); but here in the vision a distinction is made between the prophet and the person whom he stations upon the watch-tower (specula). The prophet divides himself, as it were, into two persons (compare Isaiah 18:4 for the introduction; and for the expression "go," Isaiah 20:2). He now sees through the medium of a spy, just as Zechariah sees by means of the angel speaking in him; with this difference, however, that here the spy is the instrument employed by the prophet, whereas there the prophet is the instrument employed by the angel.

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.

21:6 Go set - This was now done only in a vision, but it signified what should be done really afterwards.

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."

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.