Revelation 9:17; Horses In the Vision

Revelation 9:17 And thus I saw the horses in the vision, and them that sat on them, having breastplates of fire, and of jacinth, and brimstone: and the heads of the horses were as the heads of lions; and out of their mouths issued fire and smoke and brimstone. 

Before describing the horses, the actual agents of destruction, John briefly described those who sat on them. He noted that the riders had breastplates the color of fire and of hyacinth and of brimstone. The color of fire is red; that of hyacinth, dark blue or black like smoke; that of brimstone, a sulfurous yellow, describing the rock which, when ignited, produces a burning flame and suffocating gas. Those are the very colors and features of hell (cf. 14:10; 19:20; 20:10; 21:8), and they paint a terrifying picture of God’s wrath poured out on the sinful world by these demons. These colors are reminiscent of the destruction of Sodom, Gomorrah, and the nearby cities (Gen. 19:24–28).

Horses are frequently associated with warfare in Scripture (e.g., Ex. 14:9ff.; Deut. 11:4; 20:1; Josh. 11:4; 1 Sam. 13:5; 2 Sam. 1:6; 8:4; Ps. 33:17; Prov. 21:31; Isa. 5:28; Jer. 6:23; Ezek. 23:23–24; 38:4, 15; Dan. 11:40; Hos. 1:7; Joel 2:4; Nah. 3:2–3), but it is clear that these are not actual horses. Using the descriptive language of his vision, John noted that the heads of the horses were like the heads of lions. Like lions these demon forces fiercely, relentlessly, determinedly stalk and slaughter their victims. John noted three ways that the demon horses killed their victims, all of which picture the violent, devastating fury of hell. They incinerated them with fire, and asphyxiated them with smoke and brimstone. John saw that the devastating result of this deadly demonic assault was to be that a third of mankind was killed by these three plagues, by the fire and the smoke and the brimstone which proceeded out of their mouths.

 MacArthur, J. F., Jr. (1999). Revelation 1–11 (p. 271). Chicago: Moody Press.