C. F. Keil and Franz Delitzsch on Isaiah 33:2

Isa 33:2

In Isa 33:2 the prophet’s word of command is changed into a believing prayer: “Jehovah, be gracious to us; we wait for Thee: be their arm with every morning, yea, our salvation in time of need!” “Their arm,” i.e., the power which shelters and defends them, viz., Thy people and my own. “Yea,” 'aph, is emphatic. Israel’s arm every morning, because the danger is renewed every day; Israel’s salvation, i.e., complete deliverance (Isa 25:9), because the culminating point of the trouble is still in prospect.