Revelation 9:17

having breastplates This must be understood of the riders chiefly, but perhaps not exclusively: comparing Revelation 9:9 we cannot be sure that St John would not use the word "breastplate" of the defensive armour of a horse, if he had such in his mind. In fact, the word is used in later Greek of defensive armour generally, not the breastplate only.

of fire, and of jacinth, and brimstone All these are expressed in Greek by adjectives. The last means only "likebrimstone;" and though the terminations of the two former would properly indicate the material, yet the "jacinth" seems so incongruous with the other two, that it is easiest to understand all three as referring to colour only: they had breastplates of fiery red, of smoky blue, and of sulphurous yellow. Whether all had tricoloured armour, or whether there were three divisions, each in a distinctive uniform, may be doubted: but the three plagues corresponding to these colours, which we hear of directly after, are almost certainly inflicted by the whole army alike: and this affords some presumption that the attire of all was symbolical of all three.