The unclean spirits are not real frogs, they are the spirits of demons.

         They are the seducing spirits who go forth preaching the Doctrines of Devils in the latter times.

         They are sent out by the Satanic Trinity: 
                           The Dragon - Satan
                           The Beast - Antichrist
                           The False Prophet 
The Interval Between
The Sixth and Seventh Vials
Three Unclean Spirits
Revelation 16:13-16

"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 (demons), 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 (Armageddon) 
Behold I come as a their.  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 Har-Mageddon.
The prophecy in Isaiah says, "the Lord shall utterly destroy the tongue of the Egyptian Sea  (Red Sea)  and . . . shake His hand over the River Euphrates and smite its seven streams, so men can go over dry shod", referring to this time.

       The Kings will journey from the East and from the West and meet in Palestine for the Battle of Armageddon.
The Sixth Vial
The River Euphrates Dried Up
Revelation 16:12

"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."

        This means the literal river Euphrates dried up like all the other plagues are literal.  It is to be dried up so the Kings of the East and their armies can cross over and ready themselves for the Battle of Armageddon.
In Mark, Jesus speaks of the Fifth Vial as the time when "the Sun shall be darkened and the Moon shall not give her light."

         This Plague follows the Plague of scorching heat as if God in mercy would hide the Sun whose rays had been so hard to bear.

                   The effect of the darkness was that men gnawed their tongues for the pain and for their sores, showing that these Plagues overlapped each other or followed in such rapid order that they were not over suffering of one before they suffered another.

Their sufferings brought no repentance but caused them to blaspheme the God of Heaven. 
The Fifth Vial
Darkness
Revelation 16:10-11

"And the Fifth Angel poured out his Vial upon the seat (throne) 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 pain and their sores and repented not of their deeds."

           This is a repetition of the Ninth Egyptian Plague, that of the darkness.  The prophet Joel spoke of this day, "A day of darkness and gloominess, a day of clouds and thick darkness."
The Fourth Vial isn't a repeat of the Fourth Trumpet.

        Here the heat of the Sun is much greater and so great that men are scorched by it.  It is the time spoken of by Malachi, "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"; and the time is located just before the Sun of Rightousness shall arise with healing in His wings.
The Fourth Vial
Great Heat
Revelation 16:8-9

"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."
John heard the Angel of the Waters say, "Thou art righteous, O Lord, which art and wast and shall 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,"   or  deserve it.

        Those will be awful times when there will be nothing but blood to quench the thirst.
The Third Vial
Blood on the Rivers and Fountains
Revelation 16:4-7

"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."

       This is a repetition of the First Egyptian Plague.  When the waters of Egypt were turned to blood all the fish died. Here nothing is said about the life in the rivers or ponds.
The Second Vial
Blood On the Sea
Revelation 16:3

"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."

               At the sounding of the Second Trumpet the third part of the sea became blood and the third part of the creatures which were in the sea, died and the third part of the ships were destroyed.

                        But here all the sea is affected.  This may mean only the Sea of Galilee or the Mediterranean Sea and not the oceans.
The effect that the Plague of Boils had on the Egyptians was to harden their hearts.

           The effect will produce the same on the followers of the Antichrist by the Plagues that will be poured out of the Vials, because we see that men will blaspheme God and refuse to repent.

                        So then, suffering doesn't lead to repentance.
The Vials and what is in them are literal, and are yet to be fulfilled.

       4 of the 7 Vials are repetitions of the Plagues of Egypt.  

               The First Vial Judgment will be a repetition of the Sixth Egyptian Plague and that it actually happens is not in doubt.
First Vial
Boils
Revelation 16:1-2

"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.
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."
Here we see the Heavenly Temple and the Seven Angels that come out of it are clothed in priestly garments and the Golden Vials that they carry are given to them by one of the Beasts or Living Creatures, but which one isn't told.

         And when he gives them the Heavenly Temple fills with smoke.  Smoke means judgment.
The Tabernacle of Testimony
Revelation 15:5-8.

"And after that I looked and behold, the Temple of the 'Tabernacle of Testimony in Heaven was opened: and the Seven Angels came out of the Temple, having the Seven Plagues, clothed in pure and white linen and having their breasts girded with golden girdles.
And one of the Four Beasts gave unto the Seven Angels Seven Golden Vials full of the Wrath of God, who liveth for ever and ever.
And the Temple was filled with smoke from the Glory of God and from His Power: and no man was able to enter into the Temple, till the Seven Plagues of the Seven Angels were fulfilled."
Those with the harps are the Harpers whose song only the 144,000 Sealed Ones can sing.

         John had only heard them, now he sees them.  They can only sing both the Song of Moses and the Song of the Lamb, implying that they are Israelites.

                   They sang the Song of the Lamb because they had been redeemed by the blood of the Lamb.
This Sea of Glass is the same Sea of Glass that was before the Throne.

        Then no one was on it and its surface was crystal clear, but now it is occupied and its surface is fiery representing the fiery trials of those that are there.  

                They have come out of the Great Tribulation and have gotten the victory over the Beast, his Image, his Mark and over the number of his name and they have harps and are singing.
The Sea of Glass
Revelation 15:2-4

"And I saw as it were a sea of glass mingled with fire: and them that had gotten the victory over the Beast and over his Image and over his Mark and over the number of his name, stand on the sea of glass, having the Harps of God.
And they sing the Song of Moses the servant of God and the Song of the Lamb, saying, great and marvelous are thy works, Lord God Almighty; just and true are thy ways, thou King of Saints. Who shall not fear thee, O Lord and glorify thy name? for thou only are holy! for all nations shall come and worship before Thee; for thy judgments are made manifest."
The Seven Last Plagues 
or Vials Judgments
Revelation 15:1

"And I saw another sign in Heaven, great and marvelous, seven angels having the seven last plagues; for in them is filled up the wrath of God."

         It completed the pouring out of the 'wrath of God.'
The Winepress is the fierceness and wrath of Almighty God.

          The slaughter will be so great that the blood will be up to the horses bridles in the valleys over Palestine for 1600 furlongs, or 200 miles.

                   Isaiah the prophet said that it will be a time when the land shall be drunk with blood.
Jesus Himself became the True Vine and His disciples are the branches.

          John saw the vine of the earth, Antichrist and all who belong to his system.
The Vintage is of the vine of the earth.

        Israel was a Vine brought out of Egypt and planted in Canaan, but when God looked for it to bring good grapes it brought wild grapes, and fruit unto itself.
The difference between the Harvest and the Vintage is that the harvest in the natural world is before the Vintage but often continues until they become one.
The Battle of Armageddon takes place after the Fall of Babylon.

        We are told that the harvest is ripe and the Son of Man is commanded to thrust in His sickle, and He does, and while the pouring out of the Vials is part of the reaping.  The harvest is not finished until the end of the Battle of Armageddon.
The Harvest and Vintage are judicial.  They are for the purpose judgment.

             It looks forward to how the armies of the world are to get together by the three unclean spirits to the Battle at Armageddon.
The Reaper of the Harvest of the Earth is the Son of Man, Jesus Himself.

           He was the Sower and He is the Reaper.

                   This is not the harvest of the Church. This is the harvest of the Gentile Nations.