16:1 I heard a loud voice out of the temple, saying to the seven angels,
 

"Go and pour out the seven bowls of the wrath of God on the earth!"

16:2 The first went, and poured out his bowl into the earth, and it became a harmful and evil sore on the people who had the mark of the beast, and who worshiped his image.

16:3 The second angel poured out his bowl into the sea, and it became blood as of a dead man. Every living thing in the sea died.

16:4 The third poured out his bowl into the rivers and springs of water, and they became blood.
16:5 I heard the angel of the waters saying,
 

"You are righteous, who are and who were, you Holy One,
because you have judged these things.
16:6 For they poured out the blood of the saints and the prophets,
and you have given them blood to drink. They deserve this."

16:7 I heard the altar saying, "Yes, Lord God, the Almighty,
true and righteous are your judgments."

16:8 The fourth poured out his bowl on the sun,
and it was given to him to scorch men with fire.
16:9 People were scorched with great heat,
and people blasphemed the name of God who has the power over these plagues.
They didn't repent and give him glory.

16:10 The fifth poured out his bowl on the throne of the beast,
and his kingdom was darkened. They gnawed their tongues because of the pain,
16:11 and they blasphemed the God of heaven because of their pains and their sores.
They didn't repent of their works.

16:12 The sixth poured out his bowl on the great river, the Euphrates. Its water was dried up, that the way might be made ready for the kings that come from the sunrise.
16:13 I saw coming out of the mouth of the dragon, and out of the mouth of the beast, and out of the mouth of the false prophet, three unclean spirits, something like frogs;
16:14 for they are spirits of demons, performing signs; which go forth to the kings of the whole inhabited earth, to gather them together for the war of that great day of God, the Almighty.
 

16:15 "Behold, I come like a thief. Blessed is he who watches,
and keeps his clothes, so that he doesn't walk naked, and they see his shame."

16:16 He gathered them together into the place which is called in Hebrew, Megiddo.

16:17 The seventh poured out his bowl into the air.
A loud voice came forth out of the temple of heaven,
from the throne, saying, "It is done!"
16:18 There were lightnings, sounds, and thunders; and there was a great earthquake,
such as was not since there were men on the earth, so great an earthquake, so mighty.
16:19 The great city was divided into three parts, and the cities of the nations fell.
Babylon the great was remembered in the sight of God,
to give to her the cup of the wine of the fierceness of his wrath.
16:20 Every island fled away, and the mountains were not found.
16:21 Great hailstones, about the weight of a talent,
{1 talent is about 34 kilograms or 75 pounds} came down out of the sky on people.
People blasphemed God because of the plague of the hail, for this plague is exceedingly severe.

vs 2 These plagues may be likened to the plagues of Egypt. Only those with the mark of the beast are affected.

vs 3-5 In the spirit of "an eye for an eye", God literally gives them blood for blood which they shed. Waters of blood was also the first plague of Egypt.

vs 8-11 Notice the reaction to these plagues. The people refuse to repent, but rather cursed God! This is truly a sign of hardened hearts. Even Pharoah was willing to feign repentance in the face of such plagues. These people lack the necessary humility to repent.

vs 12-16 Frogs was another plague on Egypt. By this time, the power to do miracles had been taken away from the antiChrist and the False prophet. They had only been allowed 42 months to exercise that authority. But now these other demons will also deceive people with their miracles.

If the redeemed have left the earth, then why in reference to the 6th plague would he say, "Behold, I come like a thief! Blessed is he who stays awake and keeps his clothes with him"? One possibility is that he could be making a parenthetical remark to those reading the book, rather than speaking to the people on the earth during the 6th plague. There is no narrative stating that an announcement is being made to the world, as there has been with other announcements. Rather I can imagine Jesus stopping the vision for a moment, looking straight at John and telling him these words as a warning to the Christians to make sure they don't end up in such a situation, by keeping awake and clothing themselves with Christ. Or as I would say it, making sure that they exercise the quality of faith that saves; a faith that is characterized by full conviction and endurance, being application-oriented as well.

On the other hand, he could be talking to the Jews who had not received the mark, but only after the rapture had come to believe in Christ or will come to realize who Christ is at his return. For if the believers are gone, then who are these kings gathering to attack? And what of the prophecy

"And it shall come to pass in that day, that I will seek to destroy all the nations that come against Jerusalem. And I will pour upon the house of David, and upon the inhabitants of Jerusalem, the spirit of grace and of supplications: and they shall look upon me whom they have pierced, and they shall mourn for him, as one mourneth for his only son, and shall be in bitterness for him, as one that is in bitterness for his firstborn." Zec 12:9,10

"Awake, O sword, against my shepherd, and against the man that is my fellow, saith the LORD of hosts: smite the shepherd, and the sheep shall be scattered: and I will turn mine hand upon the little ones. And it shall come to pass, that in all the land, saith the LORD, two parts therein shall be cut off and die; but the third shall be left therein. And I will bring the third part through the fire, and will refine them as silver is refined, and will try them as gold is tried: they shall call on my name, and I will hear them: I will say, It is my people: and they shall say, The LORD is my God. Behold, the day of the LORD cometh, and thy spoil shall be divided in the midst of thee. For I will gather all nations against Jerusalem to battle; and the city shall be taken, and the houses rifled, and the women ravished; and half of the city shall go forth into captivity, and the residue of the people shall not be cut off from the city. Then shall the LORD go forth, and fight against those nations, as when he fought in the day of battle. And his feet shall stand in that day upon the mount of Olives, which is before Jerusalem on the east, and the mount of Olives shall cleave in the midst thereof toward the east and toward the west, and there shall be a very great valley; and half of the mountain shall remove toward the north, and half of it toward the south. And ye shall flee to the valley of the mountains; for the valley of the mountains shall reach unto Azal: yea, ye shall flee, like as ye fled from before the earthquake in the days of Uzziah king of Judah: and the LORD my God shall come, and all the saints with thee. And it shall come to pass in that day, that the light shall not be clear, nor dark: But it shall be one day which shall be known to the LORD, not day, nor night: but it shall come to pass, that at evening time it shall be light." Zec 13:7-14:7