C. F. Keil and Franz Delitzsch on Psalms 140:1

Suppliant Cry of One Who Is Utterly Undone

The ירוּם of the personal cry with which David opens Psa 13:1-6 harmonizes with כּרם of the general lament which he introduces into Psa 12:1-8; and for this reason the collector has coupled these two Psalms together. Hitzig assigns Psa 13:1-6 to the time when Saul posted watchers to hunt David from place to place, and when, having been long and unceasingly persecuted, David dared to cherish a hope of escaping death only by indefatigable vigilance and endurance. Perhaps this view is correct. The Psalm consists of three strophes, or if it be preferred, three groups of decreasing magnitude. A long deep sigh is followed, as from a relieved breast, by an already much more gentle and half calm prayer; and this again by the believing joy which anticipates the certainty of being answered. This song as it were casts up constantly lessening waves, until it becomes still as the sea when smooth as a mirror, and the only motion discernible at last is that of the joyous ripple of calm repose.