Furbish the spears - Cleanse, brighten, and sharpen them; from the Franco-Gallic fourbir, to polish, brighten.
Brigandines - A coat of mail, especially that which was made scale fashion; one plate overlapping the other, like the scales of fish.
From the infantry the prophet proceeds to the chariots, in which the Egyptians placed great confidence.
Get up, ye horsemen - Or, “mount the steeds.”
Furbish - i. e., polish, sharpen.
Brigandines - In old times brigand meant a soldier, and we still call a division of an army a brigade, and a commander a brigadier, i. e., a brigandier, or captain of brigands. Similarly a brigandine means a soldier‘s equipment, and is put here for a coat of mail.