Albert Barnes Commentary Isaiah 33:2

"O Jehovah, be gracious unto us; we have waited for thee: be thou our arm every morning, our salvation also in the time of trouble." — Isaiah 33:2 (ASV)

O Lord - This is a solemn prayer to Yahweh, made by the Jews in their apprehension of the Assyrian invasion. It does not mean that this prayer was actually offered, but it is a prophetic representation indicating the alarm of the Jews at his approach, and their disposition to throw themselves upon the mercy of God.

We have waited for you - That is, we have looked for deliverance from this threatened invasion from your hand (compare the note at Isaiah 26:8).

Be you their arm - The arm is a symbol of strength. It is used in the Scriptures as emblematic of the divine protection, or of the interposition of God in time of calamity and danger (Exodus 15:16; Job 40:9; Psalms 44:3; Psalms 77:15; Psalms 89:21; Psalms 98:1).

Lowth proposes to read our arm instead of their arm; and the connection would seem to demand such a reading. The Vulgate and the Chaldee read it in this manner, but there is no authority from manuscripts for a change in the text. The truth seems to be that Isaiah, impelled by prophetic inspiration, here interposes his own feelings as a Jew, and offers his own prayer that God would be the strength of the nation. The form, however, is immediately changed, and he presents the prayer of the people.

Every morning - Constantly; at all times.

In the time of trouble - Referring particularly to the trouble consequent on the Assyrian invasion.