The Lord used fire and smoke and sulfur in times past to punish people (Genesis 19:24, Genesis 19:28; Isaiah 34:9–10; see also Revelation 14:10–11; Revelation 19:20). Inhaling sulfur, like smoke, irritates the airways. Those three terms give a sense of the life‑threatening, life‑choking atmosphere of hell. This atmosphere spreads across humanity so that people must invariably inhale this bad air. This characteristic again demonstrates that these horses are not literal.
17 And this is how I saw the horses in my vision and those who rode them: they wore breastplates the color of fire and of sapphire and of sulfur, and the heads of the horses were like lions’ heads, and fire and smoke and sulfur came out of their mouths.