What does Revelation 6:4 mean?
The rider on the red horse responds to the command to come and receives permission to take peace from the earth. Apparently, a measure of international peace will prevail at the beginning of the tribulation. Paul warned that "while people are saying, 'There is peace and security,' then sudden destruction will come upon them" (1 Thessalonians 5:3).The "great sword" mentioned in this verse is referred to as megalē machaira in the original Greek. The term machaira could refer to a large knife or a cutting weapon. John's description here calls to mind the gladius, the stocky two-sided sword employed by Roman foot soldiers. Many interpreters take this to mean the Roman Empire is in view in this verse. The Romans had established Pax Romana, Peace of Rome, throughout its empire, however later the empire experienced internal strife and finally collapsed. Then, it was overrun by barbarians.
Others see the reference to war here as more future-oriented, beyond even the centuries following John's writing. According to this interpretation, the war and mayhem symbolized here are part of the tribulation itself. This is the most common, and most consistent interpretation.
The color of the second horse is red, which is the color of blood. It symbolizes slaughter that follows the absence of peace. In this verse, civil war is probably in mind: people slaying one another with the sword. This description of human slaughter following the first horseman seems to rule out the interpretation that Christ is the rider portrayed in verse 1.