Saying to the sixth angel which had the trumpet, Loose the four angels which are bound in the great river Euphrates.

saying to the sixth messenger who had the trumpet, 'Loose the four messengers who are bound at the great river Euphrates;'

It said to the sixth angel - the angel who had the trumpet, "Set at liberty the four angels who are prisoners near the great river Euphrates."

Saying to the sixth angel who had the horn, Make free the four angels who are chained at the great river Euphrates.

saying to the sixth Angel who had the trumpet: "Release the four Angels who were bound at the great river Euphrates."

It spoke to the sixth angel – the angel with the trumpet – and said 'Let loose the four angels that are in chains at the great river Euphrates.'

Saying to the sixth angel, which had the trumpet - See the notes at Revelation 8:2.
Loose, - This power, it would seem, was given to the sixth angel in addition to his office of blowing the trumpet. All this, of course, was in vision, and cannot be literally interpreted. The meaning is, that the effect of his blowing the trumpet would be the same as if angels that had been bound should be suddenly loosed and suffered to go forth over the earth; that is, some event would occur which would be properly symbolized by such an act.
The four angels - Compare the notes at Revelation 8:2. It was customary to represent important events as occurring under the ministry of angels. The general meaning here is, that in the vicinity of the river Euphrates there were mighty powers which had been bound or held in check, which were now to be let loose upon the world. What we are to look for in the fulfillment is evidently this - some power that seemed to be kept back by an invisible influence as if by angels, now suddenly let loose and suffered to accomplish the purpose of desolation mentioned in the subsequent verses. It is not necessary to suppose that angels were actually employed in these restraints, though no one can demonstrate that their agency was not concerned in the transactions here referred to. Compare the notes on Daniel 10:12-13. It has been made a question why the number four is specified, and whether the forces were in any sense made up of four divisions, nations, or people. While nothing certain can be determined in regard to that, and while the number four may be used merely to denote a great and strong force, yet it must be admitted that the most obvious interpretation would be to refer it to some combination of forces, or to some union of powers, that was to accomplish what is here said. If it had been a single nation, it would have been more in accordance with the usual method in prophecy to have represented them as restrained by an angel, or by angels in general, without specifying any number.
Which are bound - That is, they seemed to be bound. There was something which held them, and the forces under them, in check, until they were thus commanded to go forth. In the fulfillment of this it will be necessary to look for something of the nature of a check or restraint on these forces, until they were commissioned to go forth to accomplish the work of destruction.
In the great river Euphrates - The well-known river of that name, commonly called, in the Scriptures, "the great river," and, by way of eminence, "the river," Exodus 23:31; Isaiah 8:7. This river was on the east of Palestine; and the language used here naturally denotes that the power referred to under the sixth trumpet would spring up in the East, and that it would have its origin in the vicinity of that river. Those interpreters, therefore, who apply this to the invasion of Judaea by the Romans have great difficulty in explaining this - as the forces employed in the destruction of Jerusalem came from the West, and not from the East. The fair interpretation is, that there were forces in the vicinity of the Euphrates which were, up to this period, bound or restrained, but which were now suffered to spread woe and sorrow over a considerable portion of the world.

Loose the four angels - These four angels bound - hitherto restrained, in the Euphrates, are by some supposed to be the Arabs, the Saracens, the Tartars, or the Turks; by others, Vespasian's four generals, one in Arabia, one in Africa, one in Alexandria, and one in Palestine.

Saying to the sixth angel which had the trumpet, (12) Loose the four angels which are bound in the great river Euphrates.
(12) As if he should have said, these till now have been bound by the power of God, that they could not freely run over all men as they lusted, but were held and restrained at that great river of Euphrates, that is, in their spiritual Babylon (or this is a paraphrase of the spiritual Babylon, by the limits of the visible Babylon long since overthrown) that they might not commit those horrible slaughters, which they long breathed after. Now go to it, let loose those four angels, that is, administers of the wrath of God, in that number that is convenient to the slaughtering of the four quarters of the world: stir them up and give them the bridle, that rushing out of that Babylon of theirs, which is the seat of the wicked ones, they may fly over all the world, therein to rage, and most licentiously to practise their tyranny, as God has ordained. This was done when Gregory the ninth by public authority established as Law, his own Decretals, by which he might freely lay traps for the life of simple men. For who is it that sees not that the laws of Decretal, most of them are snares to catch souls with? Since that time (O good God) how many great slaughters have there been? How many great massacres? All history is full of them: and this our age abounds with most horrible and monstrous examples of the these.

Saying to the sixth angel which had the trumpet,.... The sixth trumpet, which was given him, and he had prepared himself to sound, and had sounded:
loose the four angels which are bound in the great river Euphrates; not the four angels in Revelation 7:1; they stood upon the four corners of the earth; these were in, or at the river Euphrates; they held the four winds, that they should not blow, or restrained the savage nations, that they should not hurt; these are bound themselves, that they might not do mischief; nor are angels by nature at all intended; not evil angels, though they are bound in chains of darkness, and are reserved to judgment, they are admitted indeed to rove about in the air and earth, but are under the restraints of the power and providence of God; nor good angels, who are at the divine beck, and go in and out, and are detained and sent forth according to the pleasure of God, and are sometimes employed in killing great numbers of men; see 2-Samuel 24:15; but men are here meant, as appears from Revelation 9:16, and particularly the Turks, as most interpreters agree; who dwelt on the other side the river Euphrates, and were let loose, or suffered to pass over that river into the eastern empire, to ruin and destroy it, as they did: these are called "angels", because of their might and force, their power and strength, with which they bore all before them; and for their great swiftness and rapidity in the victories and conquests which the Ottoman family obtained; who, from very small beginnings, raised themselves, in a very little time, to a large monarchy, and founded the Turkish empire, which, from them, is to this day called the Ottoman empire. Ottoman the First subdued great part of Bithynia, and fixed the seat of his kingdom at Prusa; or rather his son Urchanes, who conquered Mysia, Lycaonia, Phrygia, Caria, and the rest, to the Hellespont, and the Euxine sea. Amurath his son took Callipolis, Hadrianople, and the adjacent provinces. Bajazet added to the empire Thessalia, Macedonia, Phocis, Attica, Mysia, and Bulgaria; and Mahomet the Second took Constantinople itself, and thereby put an end to the eastern empire; and all this was done in a very few years: it is said of this last, that he conquered two empires, and twelve kingdoms, and above two hundred cities (a). And these Ottoman Turks may be called angels, or messengers, because they were the messengers and executioners of God's wrath upon the eastern empire: they are signified by "four angels", either, as some think, because of the four names of Saracens, Turks, Tartars, and Arabians, though all Mahometans, under which they went, before they were united under one emperor, Ottoman; or rather because of the four principalities, or governments, into which they were divided, while they were upon the banks of, or near to the river Euphrates; the seat of one being at Iconium, another at Bagdad, a third at Aleppo, and a fourth at Damascus; and chiefly because, when they passed the river Euphrates, they had four princes at the head of them, Soliman Shak, and his three sons. Soliman himself, as he passed, not knowing the fords of the river, was drowned in it; at which his sons being so affrighted, two of them, Sankur Zengi, and Gun Tugdi, returned to Persia, but the third, Ortogrules, with his three sons (which made "four" again) Condoz, Sarubani, and Othman, or Ottoman, continued, to whom Aladdin, sultan of Iconium, gave them some land among the mountains of Armenia (b); and from hence, by degrees, as before observed, a large empire was raised. Now these are said to be "bound in the great river Euphrates"; which river is to be literally understood, and is the same with that which is so called in Genesis 2:14, and ran through Mesopotamia and Chaldea, and was the boundary of the Roman empire; so it was fixed by Hadrian (c); and beyond which the Turks, before this time did rarely go, and if they did, retired again: for till this time, as the historian says (d), the Turks had Asia, , "within Euphrates", and the Arabians Coelo-Syria and Phoenicia. Now here these were bound; they were not suffered to pass the river, or to make any inroads of any consequence further into the Roman empire; they were restrained, by the decree of God, from proceeding any further till this time; which, as he fixes a decreed place for the sea, that its waves should come thus far, and no further, so he restrains princes from their enterprises, and settles the bounds of empires, as long as he pleases; and they were kept back by the power of God from pouring in upon the empire, and pouring forth their fury upon it, who causes the wrath of men to praise him, and restrains the remainder of it; and they were also prevented from coming any further, as yet, through the internal divisions among themselves, and by the victories of the Christians in Palestine.
(a) Petav. Rationem. Temp. par. 1. l. 9. c. 7. (b) Pocock, Supplem. Hist. Dynast. Abulpharaji, p. 41, 42. (c) Rufi Fest. Brev. p. 368. Eutrop. Hist. Roman. l. 8. p. 502. (d) Nicephor. Gregor. Hist. Roman, l. 2. p. 29.

in, &c.--Greek, "epi to potamo"; "on," or "at the great river."
Euphrates--(Compare Revelation 16:12). The river whereat Babylon, the ancient foe of God's people was situated. Again, whether from the literal region of the Euphrates, or from the spiritual Babylon (the apostate Church, especially ROME), four angelic ministers of God's judgments shall go forth, assembling an army of horsemen throughout the four quarters of the earth, to slay a third of men, the brunt of the visitation shall be on Palestine.

Loose the four angels - To go every way; to the four quarters. These were evil angels, or they would not have been bound. Why, or how long, they were bound we know not.