We have no such description or representation as this in any other place of holy writ. Some understand it of the several coloured breastplates that the soldiers wore; some of a red and flaming colour, like fire; others blue, like the jacinth; some pale: all such as wear them look terribly. Mr. Mede hath here again a peculiar notion; thinking that the Holy Ghost doth here signify their fighting with great guns, (not known before the siege of Constantinople), which throw out fire and smoke, &c., and so alter the air, the medium by which we see, that the opposite party in fighting appear to those that use these arms, as if they were covered with breastplates that were red, and blue, and pale. To confirm this, he tells us of Chalcondylas's report of this siege, who mentioneth great guns used at it of that vast bigness, that one of them required threescore and ten yoke of oxen and two thousand men to draw it, &c. It is at least a very ingenious conjecture, and I could not but mention it in honour to the learned author; leaving it to my reader's liberty, whether he will, with Mr. Mede, judge this literal sense of the text is best, or interpret all these phrases more generally, only of a terrible appearance of those armies.
Related Commentaries of Revelation 9:17
Revelation 9:17
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.