Rivers of Blood
Rev 16:1 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 voice of God ordering the angels to pour out the vials of wrath on the earth.
Rev 16:2 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.
Those who had the mark of the beast received the wrath of God. The first vial brought forth noisome (evil) grievous sores or boils. The old testament was a type of future realities. Egypt received God's judgment of boils too.
Exo 9:10 And they took ashes of the furnace, and stood before Pharaoh; and Moses sprinkled it up toward heaven; and it became a boil breaking forth with blains upon man, and upon beast.
Exo 9:11 And the magicians could not stand before Moses because of the boils; for the boil was upon the magicians, and upon all the Egyptians.
Rev 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.
Other translations say that every living creature in the sea died. The sea became as a man's blood, destroying all life.
Rev 16:4 And the third angel poured out his vial upon the rivers and fountains of waters; and they became blood.
In Egypt, the Nile River turned to blood as God poured out His wrath with Moses interceding.
Exo 7:17 Thus saith the LORD, In this thou shalt know that I am the LORD: behold, I will smite with the rod that is in mine hand upon the waters which are in the river, and they shall be turned to blood.
Exo 7:18 And the fish that is in the river shall die, and the river shall stink; and the Egyptians shall loathe to drink of the water of the river.
The angel poured out the third vial and all the rivers and fountains of the world became blood.
Rev 16:5 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.
Rev 16:6 For they have shed the blood of saints and prophets, and thou hast given them blood to drink; for they are worthy.
Blood for blood, as when Abel's blood cried out for vengence from the ground.
Gen 4:10 And he said, What hast thou done? the voice of thy brother's blood crieth unto me from the ground.
Gen 4:11 And now art thou cursed from the earth, which hath opened her mouth to receive thy brother's blood from thy hand;
Luke 11:51 From the blood of Abel unto the blood of Zacharias, which perished between the altar and the temple: verily I say unto you, It shall be required of this generation.
Rev 16:7 And I heard another out of the altar say, Even so, Lord God Almighty, true and righteous are thy judgments.
Perhaps the voice of Jesus and the cross? For he died without sins at the hands of sinners. He died for you and me and all the world. The time was running out, it is the very last days, no water to drink, grievious sores and more to come. If we think we have it bad, if we are in Christ Jesus we are most blessed. Those who do not want Jesus must face God's wrath.