Verse 8: And the second angel sounded, (Jer. 51:25; Amos 7:4) and as it were a great mountain burning with fire was cast into the sea: (Rev. 16:3) and the third part of the sea (Ezek. 14:19) became blood…
[A great mountain burning with fire was cast into the sea] Terrors and prodigies increase by degrees (Menochius, Ribera). A mountain burning, Jeremiah 51:25. There is a casting of a mountain into the sea, Psalm 46:2 (Grotius). Mountains are able to be moved, 1 Corinthians 13:2, and to be cast into the sea, Matthew 17:20 (Cluverus). A mountain, etc., that is, a certain fiery globe (Ribera, Menochius). That mountain is, either, 1. the Antonia citadel near the Temple. For it is common among the Prophets to give to citadels the name of mountains, Isaiah 13:2; Ezekiel 38:20; Micah 1:4; 3:12; 4:1; Amos 6:1; Obadiah 8, 9. Again, by citadels are understood those that were dwelling in citadels, as it appears out of the same passages. Wherefore, just as by mountain is to be understood Antonia, so by Antonia are to be understood the soldiers that were in Antonia, who all were poured out with great anger upon the people of Jerusalem, which is here called by the name of sea, as in Revelation 7:1, 3 (in which place see the things said); 4:6; Daniel 7:2. The event here predicted is narrated by Josephus in his Antiquities 20:4 and Jewish War 1:20 (Grotius). Or, 2. that great multitude of seditious men in Galilee (which could be designated here by sea, with regard to the sea of Tiberias), which men Vespasian, dispatched by Nero, subjugated and afflict with the greatest slaughter (Hammond). Or, 3. the Devil (certain interpreters in Pareus, Gagnæus), as Primasius, Bede, and others maintain (Cluverus), and a great many Interpreters, Papist and ours (Pareus); who is called a mountain on account of his pride, great on account of his power (certain interpreters in Pareus), burning with wrath and hatred (Pareus, Cluverus, Gagnæus), on account of the preaching of the Gospel (Pareus); cast into the sea, that is, into this brackish and restless world (Gagnæus), into the world or hearts of reprobates (Cluverus); or, among the peoples and princes, urging them against Christ and the Church, etc. (Pareus). But this exposition is too general (Cluverus). And from the beginning the Devil has done this, so that there was no need for John to represent it by an obscure type (Pareus). Or, 4. the City of Rome, here signified by a mountain, as was also Babylon, Jeremiah 51:25. Compare Isaiah 13:2. The Sea of the political World, as I said, is the fullness of Dominion, as it is evident from a comparison of Isaiah 19:5; Jeremiah 51:36, 44; Ezekiel 31:4. Thence the Empires in Daniel ascend out of the Sea, that is, they arise out of the fullness of Dominion. That this Mountain is said to be cast into the Sea, τὸ πρέπον, the correspondence, is figurative, since on no other account is a Mountain able to strike a Sea except it be cast into it. It means this, that into Rome, once and again seized, spoiled, and burning with the flames of enemies, disaster unto the dissolution of the fullness of Roman dominion and jurisdiction broke; its provinces, because of the weakness of the head thus afflicted, were now for the pleasure of the Barbarians, pillaging and tearing them apart into new Kingdoms, etc. (Mede’s Works 763). Or, 5. the Imperial power, which is said to be burning and cast into the sea, that is, into the multitude of peoples, as in Jeremiah 51:36, 42, on account of the incredibly fierce persecutions and slaughters with which it afflicted Christians, and its own people, and nearly the whole world (Lightfoot’s Harmony, Chronicle, and Order of the New Testament 157). Or, 6. War, which has its own danger: A great mountain, that is, sharp war, burning, most severe and terrible, more severe by far than that of the second Seal, raging after the likeness of fire; cast into the sea, that is, by an angry God hurled against the Dominions and principalities of this world, which are perpetually agitated after the likeness of the Sea, and suffer their own seethings and reciprocal recedings. In this place are denoted wars, greater than at any other time, incredibly great disturbances in the World, immense slaughters, Kings driven from their kingdoms, Rome overthrown by barbarians, the Church especially troubled, etc. (Cotterius). [The particular layout of the disturbances and wars see in Cotterius.] Or, 7. some notable heretic (Piscator): or, the class of Encratites and Montanists, and Cataphrygians, who are compared to a burning and shining mountain, both on account of the false presence of God among them, and on account of their singular sanctity of life, which they were professing. The Sea here is the Church, which they corrupted with their errors (Gravius). Or, 8. Men, distinguished with authority in the Church, or the Governors of the Church. For Mountains in Scripture denote Powers, Jeremiah 51:25; Zechariah 4:7. Now, as if a great mountain is the expression used, so that it might be apparent that the mountain is here understood figuratively, not properly, after a mountain like Ætna, Hecla, etc., which burn within themselves, etc. Fire here denotes contention, just as in Judges 9:20, 23, and ambition, with which Ecclesiastical men were aroused, striving fiercely for the supremacy soon after the Nicean Council, as it is well-known. Now, this Trumpet aptly follows the first, or the Trumpet of Heresies, inasmuch as it arises from thence, etc. (Durham). The fire of the prior Trumpet was of contention; the fire of this one is of ambition, whereby directly they were disputing concerning prerogatives and places. Mountains in Scripture are put for lofty and magnificent positions (Forbes). By sea here one is able to understand, either, 1. the multitude of the peoples, as in Revelation 17:15, for this evil crept from Ecclesiastical men to the common people: or, 2. places across the sea, and separated from Judea by the sea placed between, which sort are Africa, Rome, and Western locations, which this distaster especially pervaded: or, 3. the government and worship instituted in the Church, so that it might be signified that, just as in the prior Trumpet Doctrine is corrupted; so here the Discipline is undermined, Schisms arise, heretical Councils are held, human Inventions are introduced, etc. (Durham). Let us remember that thus these evils were arranged temporally in such a manner that also the former in contained in the latter, and the latter began to operate in the height of the former. This fiery mountain is cast into the sea, just as the former evil was cast into the earth; to denote a degree of defection greater than in the former: just as the sea is a nobler and purer element than the coarse earth. The first defection was of religion in the hearts and morals of men. The second is in the ordinary worship, which is now perverted in great part through multitudinous rites and superstitious ceremonies. After the Nicean Council, there were scandalous contentions among the Bishops concerning preeminence of place, etc. (Forbes).
[And a third part of the Sea (that is, of this world [Zegers, Cotterius]: or, of the Roman Sea [Mede’s Works 573]: or, of the Church [Pareus]) was made blood] That is, it appeared bloody (Drusius). A great part of the people were either killed or wounded (Grotius). Blood is primarily used for slaughter, then for death even without blood: However, death is used for ruin, Ezekiel 3:18, 20; 14:19; 18:13; Amos 2:2; Romans 7:9. Whence to be made blood, or bloody is an image of an event allowing violent ruin. The intention, therefore, is that Roman dominion was truncated, torn to pieces, ruined (Mede’s Works 573). Others: This is a symbol of heretical doctrine, because of which men die, like the fish with the sea turned into blood, Exodus 7:21 (Piscator, thus Durham). With Discipline undermined, and worship corrupted, Synods, Councils, and Ministers, which were formerly of the greatest use, are serviceable to the Church, not now for edification, but for ruin (Durham).
There is a great variety of senses also about this mountain of fire cast into the sea. Some by it understand things happening in Judea; but this had been not to have showed John the things which should be, but which had been. Others will have the devil understood; others, the power of the Roman empire; others, some great war stirred up amongst people; others, some notable heresy or heretic; others, some famous persons in the church: but I most like Mr. Mede’s notion again here, who understands by this mountain, Rome, the seat of the western empire; great cities being called mountains in Scripture phrase, Isaiah 37:24; Jeremiah 51:25. And the third part of the sea became blood: this phrase speaks only the great effusion of blood upon the taking of Rome by its enemies.
Verse 9: (Rev. 16:3) And the third part of the creatures which were in the sea, and had life, died; and the third part of the ships were destroyed.
[A third part of the creature, etc.] Or, of the creatures, etc. (Erasmus, Beza, Piscator), either, of Fish (Drusius, Menochius): or, of Men (Drusius, Grotius), namely, of the Jews in Galilee (Hammond). Partly by massacre, partly by the collapse of a citadel, were killed twenty thousand, says Josephus; but Eusebius says thirty thousand. Add also the vast number of animals provided for sacred rites (Grotius). The Roman Legions slaughtered by the Barbarians, etc. (Mede’s Works 573).
[A third part of the ships, etc.] Understand, [either, 1.] the many vessels of the Temple plundered by the soldiers. Just as the people are a sea, so movable objects are ships (Grotius). [Or, 2.] Cities, in which men both live and do business, and are in safety, as if in ships in the sea (Hammond). [Or, 3.] Churches with their skipper-Bishops (Pareus): or, traders, that is, the Ecclesiastical clerics, as it is evident from a comparison with Revelation 18:17 (Forbes). A ship is a type of the Church (Pareus). Or, 4. the kingdoms of this world, which rise high, excel in strength, and conduct affairs, like ships on the Sea. Ships, says he, διεφθάρησαν, that is, were corrupted, or dissolved into rottenness; but yet in such a way that they are able to be repaired (Cotterius).
And the third part, etc.: Phrases all signifying the miserable catastrophe that should follow the destruction of this city, by the slaughter of men, the ruin of houses and towns in Italy, etc. History (as Mr. Mede showeth) excellently agreeth with this. In the year 410, Rome was taken by Alaricus; this was followed with great devastations both in France and Spain. Honorius, to recover the empire, was glad to give the Goths a seat and government in France, and the Burgundians and Vandals a place near unto the river Rhone; and, AD 415, to the Vandals a place in Spain; and, AD 455, Rome was again taken by Gensericus the Vandal, who divided the whole empire into ten kingdoms: 1. That of the Britons, ruled by Vortimer. 2. The Saxons, ruled by Hengist. 3. The Franks, ruled by Childeric. 4. The Burgundians, ruled by Gundericus. 5. The Visigoths, ruled by Theodoricus II. 6. The Alans and Suevi, ruled by Riciarius. 7. The Vandals, ruled by Gensericus. 8. The Germans, ruled by Sumanus. 9. The Ostrogoths, ruled by Theodemirus. 10. The Grecians, ruled by Marcianus. This is the sum of what Mr. Mede saith, and to this tract of time, betwixt the years 410 and 455, the second trumpet seemeth to relate.
 Greek: Καὶ ὁ δεύτερος ἄγγελος ἐσάλπισε, καὶ ὡς ὄρος μέγα πυρὶ καιόμενον ἐβλήθη εἰς τὴν θάλασσαν· καὶ ἐγένετο τὸ τρίτον τῆς θαλάσσης αἷμα.  The Antonia citadel was a Roman garrison located at the northwest corner of the Temple mount where the procurator resided in Jerusalem.  Nero appointed Titus Flavius Vespasianus to crush the Jewish Revolt in 66 AD, which he managed with great success and bloodshed until 69 AD, when he was called to Rome and became emperor following Nero’s death the previous year. Vespasian’s son, Titus Flavius, continued the campaign against the Jewish rebellion, culminating in the destruction of Jerusalem in 70 AD.  The Encratites (“the self-controlled”) were second century ascetic Gnostics; they taught that one should abstain both from meats and marriage.  The Montanists were a second century sect; they were followers of the heretic Montanus, and they were known for their ecstatic utterance in the name of the Holy Spirit.  The Cataphrygians were followers of Montanus from Phrygia. Mount Ætna (in Italy) and MountHekla (in Iceland) are two of Europe’s most notable volcanoes.  Greek: καὶ ἀπέθανε τὸ τρίτον τῶν κτισμάτων τῶν ἐν τῇ θαλάσσῃ, τὰ ἔχοντα ψυχάς, καὶ τὸ τρίτον τῶν πλοίων διεφθάρη.  The Vulgate reads the singular; the Greek text, the plural.  Flavius Honorius (384-423) reigned as Roman Emperor from 393 to 395, and as Western Roman Emperor from 395 to 423. He was the son of Theodosius I.  Genseric (c. 389-477) was King of the Vandals and Alani from 428 to 477.  Vortimer is said to have been a fifth century King of the Britons.  Hengist, or Hengest (died c. 488), was a Saxon King, said to have been a founding ruler of the British Kingdom of Kent.  Childeric I (c. 440-c. 481) was the Merovingian king of the Salian Franks, or Salii, from 457 to 481. He was the father of Clovis I.  Gundericus, or Gunther (d. 437) was a King of Burgundy.  Theodoricus II, or Theodoric II, reigned as King of the Visigoths from 453 until his death in 466.  The Suevi, or Suebi, were a Germanic tribe; they established a kingdom in the Iberian Peninsula, which kingdom only survived unto the late sixth century.  Riciarius, or Rechiar, was the Suevic King of Galicia from 448 until his death in 456. He was the first Catholic Germanic king in Europe.  Sumanus (flourished 456) is said to have been King of the Germanic Roman province of Rhætia.  The Ostrogoths were a branch of the Goths; after the breakup of the Roman Empire their territory covered much of Italy and the Balkans, as well as portions of Hispania (Spain) and Gaul (France).  Theodemir reigned as King of the Ostrogoths, jointly with his brothers, Valamir and Vidimir, from 470 until his death in 474. He was an Arian, a vassal of Attila the Hun, and father of Theodoric the Great.  Flavius Marcianus (396-457) was the Byzantine Emperor from 450 to 457.