Upon the walls of Babylon - Or, "against the walls." The King James Version takes the word ironically, as a summons to Babylon to prepare for her defense; others take it as a summons to the army to make the attack.

Set up the standard - A call to the enemies of Babylon to invest the city and press the siege.

Set up the standard upon the walls of Babylon,.... This is not said to the Medes and Persians, to put up a flag on the walls of Babylon, as a sign of victory, as Kimchi, Abarbinel, and others think; for as yet the city is not supposed to be taken by what follows; but rather to the Babylonians, to set up an ensign on their walls, to gather the inhabitants together, to defend their city, and the bulwarks of it; which, with what follows, is ironically spoken:

make the watch strong; to guard the city; observe the motions of the enemy, and give proper and timely notice; increase and double it:

set up watchmen; meaning the keepers of the walls; place them upon them, to keep a good look out, that they might not be surprised: this seems to respect the great carelessness and security the whole city was in the night it was taken; being wholly engaged in feasting and revelling, in rioting and drunkenness, having no fear of danger, or concern for their safety; with which they are tacitly upbraided:

prepare the ambushes; or, "liers in wait" (p); to second or relieve those on the walls upon occasion; or seize unawares the besiegers, should they attempt to scale the walls, and enter the city:

for the Lord hath devised and done that which he spoke against the inhabitants of Babylon; or as he hath devised, so hath he done, or will do: his purposes cannot be frustrated, his counsel shall stand; and therefore had the Babylonians been ever so industrious in their own defence, they could never have prevented their ruin and destruction, which was resolved upon, and accordingly effected.

(p) "insidiatores", Montanus, Junius & Tremellius, Piscator, Cocceius, Schmidt.

Set up the standard upon the walls of Babylon, make the watch strong, set up the watchmen, prepare the ambushes: for the LORD hath both devised and done that which he spake against the inhabitants of Babylon.

51:12 Set up - These seem to be the prophet's words to the Babylonians, rousing them out of their security. Historians tell us that the city was fortified by walls of fifty cubits high, and two hundred cubits broad, and by a very deep and large ditch.

ambushes: Heb. liers in wait

12. With all your efforts, your city shall be taken.

standard-to summon the defenders together to any point threatened by the besiegers.

51:1-58 The particulars of this prophecy are dispersed and interwoven, and the same things left and returned to again. Babylon is abundant in treasures, yet neither her waters nor her wealth shall secure her. Destruction comes when they did not think of it. Wherever we are, in the greatest depths, at the greatest distances, we are to remember the Lord our God; and in the times of the greatest fears and hopes, it is most needful to remember the Lord. The feeling excited by Babylon's fall is the same with the New Testament Babylon, Re 18:9,19. The ruin of all who support idolatry, infidelity, and superstition, is needful for the revival of true godliness; and the threatening prophecies of Scripture yield comfort in this view. The great seat of antichristian tyranny, idolatry, and superstition, the persecutor of true Christians, is as certainly doomed to destruction as ancient Babylon. Then will vast multitudes mourn for sin, and seek the Lord. Then will the lost sheep of the house of Israel be brought back to the fold of the good Shepherd, and stray no more. And the exact fulfilment of these ancient prophecies encourages us to faith in all the promises and prophecies of the sacred Scriptures.