What will God rain upon Gog and his army?
God will rain upon Gog and his bands an overflowing rain of great hailstones, fire, and brimstone. He will also plead against him with pestilence and blood. This judgment mirrors Sodom and Gomorrah, showing God's power to utterly destroy the invading force on Israel's mountains.
Les explains that in the Ezekiel passage, God comes in with His own power, pleading against Gog with pestilence and blood, and raining upon him and his bands an overflowing rain of great hailstones, fire, and brimstone. Les notes this is the same language used of Sodom and Gomorrah. The northern army will be defeated not only by its own confusion—every man's sword against his brother—but by God's tremendous power, utterly destroyed on the hills and mountains of Israel. Then in chapter 39, God declares He is against Gog, will turn him back, leave but a sixth part, and smite the bow from his left hand and arrows from his right. This illustrates how God deals with nations He judges.
And I will plead against him with pestilence and with blood; and I will rain upon him, and upon his bands, and upon the many people that are with him, an overflowing rain, and great hailstones, fire, and brimstone.