isaiah 22:6 And Elam bare the quiver with chariots of men and horsemen, and Kir uncovered the shield. - Free Bible Online

      6. Elam--the country stretching east from the Lower Tigris, answering to what was afterwards called Persia (see on Isa 21:2). Later, Elam was a province of Persia (Ezr 4:9). In Sennacherib's time, Elam was subject to Assyria (2Ki 18:11), and so furnished a contingent to its invading armies. Famed for the bow (Isa 13:18; Jer 49:35), in which the Ethiopians alone excelled them.
      with chariots of men and horsemen--that is, they used the bow both in chariots and on horseback. "Chariots of men," that is, chariots in which men are borne, war chariots (compare see on Isa 21:7; Isa 21:9).
      Kir--another people subject to Assyria (2Ki 16:9); the region about the river Kur, between the Caspian and Black Seas.
      uncovered--took off for the battle the leather covering of the shield, intended to protect the embossed figures on it from dust or injury during the march. "The quiver" and "the shield" express two classes--light and heavy armed troops.

JFB.