EXPOSITION
THIS is the first of a series of fifteen psalms assigned by their titles to David, and mostly attached to special circumstances in his life, which are said to have furnished the occasions for their composition. The school of writers which brushes aside the "titles" as unauthorized and unhistorical, and so regards itself as wholly free to assign to any psalm any date and any author that it prefers, places this among post-Captivity compositions, especially on account of Psalms 51:18, Psalms 51:19 (so Professor Cheyne, Dr. Robertson Smith, the Four Friends, and others). Those, on the contrary, who consider the "titles" to be entitled to regard and respect, even if not absolutely authoritative, find either nothing in the psalm unsuitable to David's time, or else nothing but what may well have been a subsequent addition for liturgical purposes. This is the view taken by many with respect to the last two verses. Others, however, note that the walls of Jerusalem were not built, but only in the course of being built, in David's time, and regard the whole psalm as eminently suited to the period whereto the title ascribes it (so Hengstenberg, Canon Cook, Dr. Kay, Professor Alexander, and others).
The psalm consists of an opening strophe, extending to four verses, which is an earnest prayer for mercy and forgiveness (Psalms 51:1-4); a second strophe, of eight verses, which is an entreaty for restoration and renewal (Psalms 51:5-12); a third strophe, of five verses, setting forth the return which the psalmist will make, if he is forgiven and restored (Psalms 51:13-17); and a conclusion, in two verses, praying for God's blessing on the people, and promising an ample return on their part (Psalms 51:18, Psalms 51:19).