Hath opened his armoury. A truly grand figure. The north country (the "hidden" part of the earth, as it was called in Hebrew) is regarded by the prophet as a storehouse of young and "inexhaustible" nations, from which Jehovah can at any time "bring forth weapons of his indignation."
The latter phrase, occurs again in the parallel prophecy (Isaiah 13:5), where it is evidently applied to the army of Medo-Persian invaders. For this is the work, etc.; rather, For the Lord, Jehovah of hosts, hath a work.