The several psalms confessing sin could overwhelm the guilty if all were grouped together, though a collection of four psalms, each including confession of sin, concludes Book I (Pss. 38-41). At first sight, their appearance throughout the Psalter might seem to be a random scattering. A reversal of expected chronological order appears when David’s rejoicing that he has been forgiven (Ps. 32) precedes his confession of sin as he seeks forgiveness (Ps. 51).
Yet, the Psalm 51 confession naturally and properly follows God’s formal issuance of a “summons” to heaven and earth so that He may “judge His people” (Ps. 50.4). David, as guilty king, is the first to be called forth for judgment. In another instance of deliberate placement of a confessional psalm appropriate to its context, Psalm 106 explicitly identifies the sins of the psalmist’s contemporaries with the repetitive sins of the fathers, which has led to their chastening by exile (Ps. 106.6). He concludes by placing a plea on the lips of his repentant companions: “Save us, O Lord our God, and gather us from the nations” (Ps. 106.47). These words have been placed so that they conclude Book IV while simultaneously leading naturally into the opening phrases of the following psalm as it introduces the fifth and final book of the Psalter: “Let the redeemed of the Lord say so – . . .those He gathered from the lands, from east and west, from north and south” (Ps. 107.3). The confession of sin by the psalmist has been critical in bringing about the restoration of the people.
Each of the five books of the Psalter contains its quota of psalms with serious confession of sin, though significantly more appear in Book I than in subsequent books. To a greater or lesser extent, the following psalms present the plea for forgiveness by the penitent psalmist: Psalms 6, 25, 32, 38, 39, 40, 41 (Book I); Psalms 51, 65 (Book II); Psalms 78, 85 (Book III); Psalms 103, 106 (Book IV); Psalm 130 (Book V).
From: The Flow of the Psalms: Discovering Their Structure and Theology by O. Palmer Robertson (Phillipsburg: P&R Publishing, 2015), pp. 19-20.
Owen Palmer Robertson (born in 1937) is the author, most famously, of The Christ of the Covenants (1981).