Any reader of the Confessions will be aware that, for Augustine, the reading of the Psalms was more than simply a “devotional” reading of a holy text, let alone reading to inform or instruct. The psalmist’s voice is what releases two fundamentally significant things for the Augustinian believer. It unseals deep places, emotions otherwise buried, and it provides an analogy for the unity or intelligibility of a human life lived in faith. Here is a conversation with God that has a beginning, a middle, and an end. And in the course of that conversation, the human speaker is radically changed and enabled to express what is otherwise hidden from him or her. Augustine speaks of what the psalm he is discussing (Psalm 4, Cum invocarem) “makes of him”: the act of recitation becomes an opening to the transforming action of grace (Conf. 9.4.8).
—Rowan Williams. “Augustine and the Psalms.” Interpretation 58, no. 1 (January 2004) (HT winged keel and crumpet)