Revelation 9:18

By these three plagues was the third part of men killed, by the fire and the smoke and the brimstone, which proceeded out of their mouths.

By these three plagues ... is usually applied to the "fire, smoke and brimstone" mentioned three times in these two verses (once with hyacinth instead of smoke), and which proceeded out of the horses' mouths. The use of the word "hyacinth" in this connection is interesting. The word has several meanings, and each one of them is suggestive of the terror here described: (1) It is a bulbous plant of the lily family having spike-like flowers, suggesting the weapons of ancient warfare. (2) It is the name of an ancient gem with a bluish-violet color, the color of smoke, which the word replaces in Revelation 9:17. (3) It is a plant frequently alluded to by the Greek poets, fabled to have born on its petals the words of grief.[73] Whatever definition John had in mind, all of its definitions were attended by doleful and melancholy overtones.

Whatever may be symbolized by these terrible beings, "There is no doubting the reality of those demonic forces that thrive on men's unbelief and are bent on their ruin."[74]

[73] Britannica World Language Dictionary Edition of Funk and Wagnalls Standard Dictionary (New York: Funk and Wagnalls Company).

[74] F. F. Bruce, op. cit., p. 648.