And I heard a great voice out of the temple saying to the seven angels, Go your ways, and pour out the vials of the wrath of God upon the earth.
The wrath of God, the apostle Paul said, is "against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness," Romans 1:18. The first chapter of Romans tells how men who "did not like to retain God in their knowledge" were given over to a reprobate mind.
The seven vials are spiritual plagues. They are poured out upon the earth, the sea, rivers, the sun, the seat of the beast, Euphrates, and the air, which are symbols used in prophecy. John says in the concluding verses of Revelation that the water of life is freely available to all, and that "if any man shall add unto these things, God shall add unto him the plagues that are written in this book." [Revelation 22:18] This implies that the plagues are spiritual, and apply to individuals.
And the first went, and poured out his vial upon the earth; and there fell a noisome and grievous sore upon the men which had the mark of the beast, and upon them which worshipped his image.
In Revelation 13:5-7, John described a beast rising from the sea, having seven heads and ten horns. One of the heads of the beast had received a deadly wound, that was healed.
The beast is related to all four of the beasts Daniel saw, in
the vision described in Daniel 7. Daniel's beasts were (1) a lion; (2)
a bear; (3) a leopard; (4)
a terrible, diverse beast. The fouth beast corresponds to the Roman
Empire. John's beast is a composite of all Daniel's four beasts,
and the total number of heads is the same in both prophecies, as the
leopard in Daniel's prophecy had four heads. The 10 horns of the fourth
beast are also seen in John's beast.
Patrick Fairbairn wrote: 
We notice first the representation that is given in the Apocalypse of the worldly power. In Daniel this appeared under a succession of beasts, each symbolizing a new and somewhat different form of the great monarchies of the world. But now it appears simply as a beast (chap. xiii.), a beast, however, that had the same origin with those of Daniel, like them rising out of the sea, and a composite creature, uniting together the several forms of the three first in Daniel (the lion, the bear, and the leopard), and possessing also the ten horns which were seen in the fourth. These points of coincidence with the vision of Daniel, plainly indicate a fundamental agreement, and, at the same time, such a difference as is obtained by the compression of a diversity into a unity. The beast of the Apocalypse, accordingly, is the worldly power, not in its several parts or successive forms of manifestation, but in its totality.
One of the heads of Daniel's third beast corresponds to the Seleucid empire, that included Jerusalem. The city of Jerusalem and the surrounding territory later became part of the kingdom of Judea, and a Roman Province. In the war of 70 AD, Jerusalem was destroyed. Possibly, John referred to the Province of Judea as one of the heads of the beast, that received a deadly wound.
In that case, when the Jewish state was established in Palestine after the end of WWII, the deadly wound of one of the heads of the beast was healed.
John says the name of blasphemy is upon the heads. The name "Israel," appropriated by the Jewish state, may fulfill this prophecy, as the names "Israel" and "Zion" properly belong to a "holy nation," consisting of the saints of God. Similarly, in history, the names of blasphemy were frequently invoked for various institutions in Europe, such as "the holy Roman Empire." The beast represents human governments, and Western civilization, that incorporates the heritage of the ancient empires of Babylon, Persia, Greece and the hellenistic world, and Rome.
The "noisome and grievous sore" falling on the men who worshipped the image of the beast signifies a serious spiritual affliction. Misinterpreting the land of promise in prophecy, and taking it to mean the literal territory of Canaan, leads to gross error and confusion, since the promised land of the Bible is a type, and a metaphor that represents the spiritual inheritance of the saints, as explained in Hebrews 11:16, which says of those who are of the faith of Abraham, "But now they desire a better country, that is, an heavenly: wherefore God is not ashamed to be called their God: for he hath prepared for them a city."
The first plague, evidently, is specific to individuals, and it describes a debilitating spiritual condition, that results from embracing flawed interpretations of prophecy.
And the second angel poured out his vial upon the sea; and it became as the blood of a dead man: and every living soul died in the sea.
Isaiah compared the wicked to a "troubled sea."
But the wicked are like the troubled sea, when it cannot rest, whose waters cast up mire and dirt.
The death of all those who are in the sea alludes to the flood
story in Genesis, when all who were not aboard the ark with Noah were
drowned. The second vial may represent the widespread belief that the
fate of most of mankind is to perish.
But the Gospel says that in the seed of Abraham, all nations will be blessed. Man's doctrine on the
destiny of unbelievers is contrary
to the gospel, which says that all men will be reconciled to God.
This plague is also evidently specific to individuals, and depicts an attitude towards unbelievers, or people of different beliefs, that views them as perishing or lost.
And the third angel poured out his vial upon the rivers and fountains of waters; and they became blood. And I heard the angel of the waters say, Thou art righteous, O Lord, which art, and wast, and shalt be, because thou hast judged thus. For they have shed the blood of saints and prophets, and thou hast given them blood to drink; for they are worthy. And I heard another out of the altar say, Even so, Lord God Almighty, true and righteous are thy judgments.
The rivers and fountains are the sources of drinking water.
But this water itself is figurative, and represents the spirit of
Christ, and the scriptures, that many people can't understand. Jesus
said, "He that believeth on me, as the scripture hath said, out
of his belly shall flow rivers of living water." [John 7:38]
The scriptures, which are the waters of life, have become are unpalatable
to them, like a dead man's blood. One of the reasons was
because they shed the blood of the prophets, and
rejected their words. The message of the prophets seems as
unwholesome as blood. The literal approach to interpretation of
prophecy leads to absurd conclusions; the whole subject of prophecy
seems as unpalatable as blood.
The fountains of waters turning to blood pictures the attitude
of many people to the teachings of the scripture, and the gospel.
The teachings of the Bible are viewed as distateful, like blood,
and as among the topics to be avoided in their conversation.
Like other plagues, this plague is specific to individuals. To the person who loves the word of God, it is living water.
And the fourth angel poured out his vial upon the sun; and power was given unto him to scorch men with fire. And men were scorched with great heat, and blasphemed the name of God, which hath power over these plagues: and they repented not to give him glory.
The sun is a symbol of the Gospel, and the sun clothes the woman in Revelation 12:1, who represents the Church. John the Baptist said that Jesus would baptize with water, and with fire. The fire is symbolic of judgment, and God's word, that destroys false teachings.
Jesus said, when the tares are removed from among the wheat, "Then shall the righteous shine forth as the sun in the kingdom of their Father. Who hath ears to hear, let him hear." [Matthew 13:43] The tares are bundled up and burned. The truth of the gospel burns the wicked, who resist the truth.
The sun represents the light of the gospel. Instead of a light, it seems like burning heat, to men who don't know God. This is also indicated by Malachi's prophecy: "For, behold, the day cometh, that shall burn as an oven; and all the proud, yea, and all that do wickedly, shall be stubble: and the day that cometh shall burn them up, saith the LORD of hosts, that it shall leave them neither root nor branch." [Malachi 4:1] The prophecy speaks of men as the stubble left behind in a field after the grain is harvested. And similarly, Paul wrote: "And to you who are troubled rest with us, when the Lord Jesus shall be revealed from heaven with his mighty angels, In flaming fire taking vengeance on them that know not God, and that obey not the gospel of our Lord Jesus Christ." [2 Thessalonians 1:7-8]
The destruction of flawed beliefs of men may be what is meant by men being "scorched" by the sun's heat, which may occur when God opens our minds to the Gospel, and when we understand the scriptures, and the symbols and figures of prophecy.
Like the previous plagues, the plague of the sun scorching men with fire, causing them to blaspheme, is specific to individuals.
And the fifth angel poured out his vial upon the seat of the beast; and his kingdom was full of darkness; and they gnawed their tongues for pain, And blasphemed the God of heaven because of their pains and their sores, and repented not of their deeds.
The darkness refers to the spiritual darkness, that pervades
the kingdom of the beast. Revelation 13:2 says of the beast, "the
dragon gave him his power, and
his seat, and great authority." There is great darkness in the world,
as the entire world is
deceived. [Revelation 12:9] There is no light in the kingdom of the
beast, because those in his
kingdom are not enlightened by the Gospel, which is the true
1:9. Because of that, they are "in the dark."
And the sixth angel poured out his vial upon the great river Euphrates; and the water thereof was dried up, that the way of the kings of the east might be prepared.
Commentators have various suggestions for interpreting the symbolic significance of the Euphrates River, which in some scriptures was the eastern limit of the Promised Land; Joshua 1:4. As the ancient boundary of Israel, the Euphrates River being dried up may be taken to be a figure of the boundary between the church and the world being obscured. James Burton Coffman wrote: 
Dr. Grijdamus looks upon the Euphrates as the symbolical prophetic
boundary between Christendom and heathendom.
This must be at least a part of the correct answer. One of the most hurtful and damaging corruptions of the spiritual environment is the breaching of barriers between the church and the world. Of course, that is not exactly what Grijdamus meant, but his comment suggested it. The extent of this breach is seen when a so-called Christian church ordains a homosexual preacher, throws a drinking party in the physical plant of the church itself, or teaches adultery and fornication under the guise of their being a "new morality." Plummer approached this view when he wrote, "It means that a barrier that wards off hostile hosts is lost."
The wall separating the church and the world is the wall of fire in
Euphrates flowed through the city of Babylon, and so in a spiritual sense it represents the teaching of Babylon as a symbol of false, worldly religion. No doubt, the river Euphrates refresents the flawed doctrines of Mystery Babylon. While metaphorical rivers flowing from Jerusalem represent the truth of the gospel going forth from the church, the Euphrates, in contrast, represents the flawed teachings of the harlot religious system, and worldly religion, represented by Babylon. Its knowledge and wisdom dries up. Paul wrote: "For it is written, I will destroy the wisdom of the wise, and will bring to nothing the understanding of the prudent." [1 Corinthians 1:19]
In the sixth plague, the Euphrates dried up, and three unclean spirits like frogs came out of the mouth of the dragon.
And I saw three unclean spirits like frogs come out of the mouth of the dragon, and out of the mouth of the beast, and out of the mouth of the false prophet. For they are the spirits of devils, working miracles, which go forth unto the kings of the earth and of the whole world, to gather them to the battle of that great day of God Almighty. Behold, I come as a thief. Blessed is he that watcheth, and keepeth his garments, lest he walk naked, and they see his shame. And he gathered them together into a place called in the Hebrew tongue Armageddon.
The warning about clothing indicates that this plague, too, is specific to individuals. Those who are deceived are gathered together at Armageddon, to make war against Christ. The wise depart from Babylon.
And I heard another voice from heaven, saying, Come out of her, my people, that ye be not partakers of her sins, and that ye receive not of her plagues.
If the "miracles" performed by the false prophet refer to the
wonders of modern technology, the power to call down fire from heaven, probably
represents modern warfare, with aircraft, bombs, rockets, nuclear
Coffman wrote: 
The dragon, the beast, and the false prophet were accurately identified by Summers as "the devil, godless government and false religion." Lange called these frogs "the modern nightingales who announce the new springtime of mankind." From the dirtiness and slimey nature of the frogs, we may conclude that they are the devil's propaganda agents, making a lot of noise like frogs, but being in themselves small, weak, dirty, and despicable.
Patrick Fairbairn dismissed the interpretation of the false prophet as false religion. In his view, it represented "worldly wisdom," and included science and art. Today this identification is even more appropriate. He wrote: 
According to this view,
the power here symbolized is that of worldly wisdom, comprehending
every thing in learning, science, and art, which human nature of itself
in its civilized state can attain to—the worldly power in its more
refined and spirit-like elements—its
more gifted sages and seers.
There can be no doubt, that it is the same power, which in three
subsequent passages (chap. xvi. 13, xix. 20, xx. 10) is called
expressly "the false prophet;" so that, as was already indicated by
the power of speech ascribed
to it, it belongs to the intellectual and
moral, not to the physical or political sphere. But the marked
separation in those passages between this false prophet and the whore,
or the corrupt church, and the equally marked intimacy of connection
between the false prophet and the beast, point to the conclusion we
have otherwise arrived at, of its having to do with prophecy, not in
the ecclesiastical, but in the worldly sense. The things which concern
the whore, as forming a class by themselves, have a distinct
representation; though nearly connected with the beast, and for a time
serving herself of this, she still is judged and destroyed apart. But
the false prophet never appears separate from the beast; he comes upon
the stage as the mere servant and tool of the latter, and the two both
work together, and perish in the same condemnation. They are alike,
therefore, in origin, in character, in aim, and in destiny; an
embodiment, only in different respects, of the sensual, grovelling,
ungodly, spirit of the world.
This second lamb-horned beast, then, is a personified representation of the world's gnosis—"the gnosis, falsely so called," of the apostle Paul; and hence the power professing and exercising it, is emphatically the false prophet. False—not because always or necessarily propounding things in themselves untrue, but because actuated by a wrong spirit in its investigations and pursuits—cultivating the talents, studying the works, plying the manifold resources of nature in a state of practical divorce from God and the interests of salvation, as if those were alone sufficient to bless the soul, and render the world a scene of satisfaction and delight. The teachings of such a spirit of prophecy are false, even when setting forth what is in itself true, because they ignore the existence, or belie the testimony, of what is emphatically the truth. Yet a formal opposition to this truth, though it might certainly be expected in part to characterise the operations of this power, is what it should rather, by the description given of it, seek to avoid. The lamblike horns imply as much—indicating that the power in question would strive to conceal its base origin and character, and even work upwards to a resemblance of that which has its true embodiment in the Divine Author of Christianity. The same thing is also implied in the note given of the relative period of its manifestation; the period, namely, of the last times of the worldly power: "He exerciseth," it is said, ver. 12, "all the power of the first beast before him, and causeth the earth, and them that dwell therein (all the worldly-minded), to worship the first beast, whose deadly wound was healed."
Fairbairn, I think, would probably agree that since the beast
represents "the worldly power" or worldly human society, the image of
the beast in our time includes movies, TV,
and similar media.
On the significance of Armageddon, Charles D. Alexander wrote: 
In Revelation Megiddo becomes Armageddon - a deliberate development of the name, to indicate the spiritual nature of the battle. Here under the Sixth Vial the forces of evil are assembled for the great gospel battle. The battle ground is spiritual. We war not with flesh and blood. Satan sees he has but a short time and raises up all his fury against the people of the Lord. He who leads captivity captive, the heavenly Barak, takes up the cause of His people and leads the hosts of heaven against the powers of darkness for the last time, the final glorious victory, against the combined forces of “the kings of the earth and of the whole world” (Rev. 16:14). The conflict is universal. The picture in Revelation defies any interpretation of a geographical battle. There is no place on earth where the armies of the whole world can assemble to destroy one little “camp of the saints” (see Rev. 20:9). Nor are we encouraged to believe that the Church as such will ever meet the combined forces of all the world’s nuclear powers, with all the latest armament of devilish science. The Church does not defend herself thus. Her armament is the armament of prayer and faith and the Word of God. By these she overcomes - and has always overcome.
And the seventh angel poured out his vial into the air; and there came a great voice out of the temple of heaven, from the throne, saying, It is done.
The seventh plague is poured out on the air, which Paul described as the domain of Satan: "Wherein in time past ye walked according to the course of this world, according to the prince of the power of the air, the spirit that now worketh in the children of disobedience:" [Ephesians 2:2]
And there were voices, and thunders, and lightnings; and there was a great earthquake, such as was not since men were upon the earth, so mighty an earthquake, and so great. And the great city was divided into three parts, and the cities of the nations fell: and great Babylon came in remembrance before God, to give unto her the cup of the wine of the fierceness of his wrath.
The judgment of Babylon is the subject of chapter 17.
And every island fled away, and the mountains were not found.
Mountains and islands being moved out of their places is also
mentioned in Revelation
6:14. Many commentators think these mountains and islands represent
the human governments and organizations. Isaiah said, "Every valley
shall be exalted, and every mountain and hill shall be made low," Isaiah 40:4.
Perhaps it means that the mysteries and
puzzles of God's word will be solved. The church is the mountain of the
Lord's house in Isaiah
2:2, and the kingdom of God, a mountain that fills the entire
Maintains and islands that are displaced include the promises of God
in scripture that are misunderstood, misinterpreted, and wrongly
applied to unbelieving Jews.
And there fell upon men a great hail out of heaven, every stone about the weight of a talent: and men blasphemed God because of the plague of the hail; for the plague thereof was exceeding great.
Lightnings, and voices, and thunderings, and an earthquake, and
great hail are also mentioned in Revelation 11:19, in the account of
trumpet. Rain and snow are symbolic of God's word, in the
prophecy of Isaiah, so hail represents God's word coming as a severe
judgment, and strong reproof. The knowledge of God comes from the
church to the world.
For as the rain cometh down, and the snow from heaven, and returneth not thither, but watereth the earth, and maketh it bring forth and bud, that it may give seed to the sower, and bread to the eater:
So shall my word be that goeth forth out of my mouth: it shall not return unto me void, but it shall accomplish that which I please, and it shall prosper in the thing whereto I sent it.
The great earthquake that occurs when the seventh plague is poured out may represent dramatic changes in how the Bible is understood. Hail the weight of a talent alludes to the parable of Jesus about the talents. [Matthew 25:14-30] Those who adopt a literal approach to interpreting prophecy are represented by the person in the parable who buried his talent in the ground. Misunderstanding, and the literalist approach, may cause people to blaspheme. See The great hail of Revelation 16:21.
1. Patrick Fairbairn. Prophecy viewed in respect to its distinctive nature, its special function, and proper interpretation. Published by T. and T. Clark, 1865.
2. James Burton Coffman. James Burton Coffman Commentary
5. Charles D. Alexander. Revelation Spiritually Understood. Part 20.
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