Hear me when I call, O God of my righteousness. Not "the God who imputes to me righteousness," as some render, but "the God who sees that I and my cause are righteous," and who wilt therefore certainly lend me aid.
Thou hast enlarged me; or, made room for me—"set me at ease" In the language of the Old Testament, "straits" and "narrowness" mean trouble and affliction; "room," "space," "enlargement," mean prosperity.
David has experienced God's mercies in the past, and therefore looks for them in the future (comp. Psalms 3:7). When I woe in distress; literally, in [my] distress. Have mercy upon me, and hear my prayer.
This is David's usual cry, repeated in a hundred varied forms throughout the Psalms (see Psalms 5:2; Psalms 6:2; Psalms 9:13; Psalms 27:7; Psalms 30:10, etc.).