He saith nothing of the infantry, but leaves us to conjecture how great that must be, from the number of the horse; we must not think there was precisely this number, but the meaning is, that the armies should be vastly great, as we know all the Turkish armies are. Magog's army is described from the cavalry, Ezekiel 38:4,15.
Related Commentaries of Revelation 9:16
Revelation 9:16
16 And the number of the army of the horsemen were two hundred thousand thousand: and I heard the number of them.