To understand the Book of Revelation, we need to study the Old Testament, particularly the writings of Zechariah, Daniel, Joel, Ekeziel and other prophets. For example, Ekeziel 14: 12-19 enhances our understanding of Revelation 6: 7-8.
The beginning of Ekeziel 14 targets sin and idolatry. Verses 12-19 pronounce judgement. Notice that Ekeziel and Revelation both speak of “famine,” “wild beasts,” “plague” and a “sword.”
The word of the LORD came to me: “Son of man, if a country sins against me by being unfaithful and I stretch out my hand against it to cut off its food supply and send famine upon it and kill its men and their animals, even if theses three men–Noah, Daniel and Job–were in it, they could save only themselves by their righteousness, declares the Sovereign LORD.
“Or if I send wild beasts through that country and they leave it childless and it becomes desolate so that no one can pass through it because of the beasts, as surely as I live, declares the Sovereign LORD, even if these three men were in it, they could not save their own sons or daughters. They alone would be saved, but the land would be desolate.
“Or if I bring a sword against that country and say ‘Let the sword pass throughout the land,’ and I kill its men and their animals, as surely as I live, declares the Sovereign LORD, even if these three men were in it, they cold not save their own sons or daughters. They alone would be saved.
“Or if I send a plague into that land and pour out my wrath upon it through bloodshed, killing its men and their animals, as surely as I live, declares the Sovereign LORD, even if Noah, Daniel and Job were in it, they could save neither son nor daughter. They would save only themselves by their righteousness” (Ezekiel 14: 12-19 NIV).
When the Lamb opened the fourth seal, I heard the voice of the fourth living creature say, “Come!” I looked, and there before me was a pale horse! It’s rider was named Death, and Hades was following close behind him. The were given power over a fourth of the earth to kill by sword, famine and plague, and by the wild beasts of the earth (Revelation 6: 8 NIV).