I often tell preachers, "If you can crack open a psalm, you'll always have something to preach, because the lectionary assigns a psalm for every Sunday."
If you do not make a regular practice of preaching on the psalms, you are excluding yourself from some rare company--such luminaries as Peter (Acts 2:25-36), Paul (Rom 3:9-20), and Luther preached on the psalms. Luther even wrote that "[The Psalter] might well be called a little Bible. In it is comprehended most beautifully and briefly everything that is in the entire Bible. It is really a fine enchiridion or handbook. In fact, I have a notion that the Holy Spirit wanted to take the trouble himself to compile a short Bible and book of examples of all Christendom or all saints, so that anyone who could not read the whole Bible would have anyway almost an entire summary of it, comprised in one little book." Unfortunately, one or two theologians have said that pastors should not preach on the psalms. We suspect that the poet who spoke Ps 58:3 had them in mind.
So, how does one crack open a psalm? How does a preacher go about preaching on this "little Bible"? One way to approach the task is to hone in on what I like to call the "central theological witness" of a psalm. In order to gain the ears to hear the theological witness of a psalm, one should attune oneself to the context of whatever psalm one is reading.
One feature of the psalms that makes them such powerful literature is that they are so breathtakingly contextual. The psalmists cry out from the depths of human despair (130:1). They sing out from the mountain tops of human joy (98:1). They confess trust of those whose feet are planted on slabs of granite (121). They express the doubts of those who cannot manage to crawl out of bed in the morning (102:6-7; 6:6). Because every human being either has been there or will be there--whether the "there" is the depths of the darkest valley or the heights of the mountain top--the contexts of the various psalms are contexts that people can relate to. So, when approaching a psalm get a feel for its context.
One approach that can help a person get a feel for a psalm's context is to use imagination and empathy. First, a person needs to imagine what sorts of situations might give birth to the words of a given psalm. Whether they are words of despair, trust, thanksgiving, instruction, or so on, the words of the psalms did not burst forth ex nihilo in Scripture. They were incarnate words--issuing forth from flesh and blood, given voice out of blood, sweat, and tears. One has to imagine the situation that gave rise to a psalm. Second, a person needs to be able to empathize with those speakers of the psalm. The intellectual exercise of imagining the ancient context is a good first step, but it is not enough. One also has to empathize, to be able to feel with and for the speakers of the psalms--in their depths, on their heights, along the paths that they walk.
Then what? Listen. Listen for the surprise. Listen for the joy. Listen for the thing that you might not expect. Listen for the singular theological witness of a psalm. Each psalm in the Psalter is unique; each psalm offers a uniquely contextualized theological witness. With some psalms, that witness is placed front and center in the psalm. Psalm 99, for example, charges out of the gate: "The Lord is king; let the peoples tremble!" With other psalms, the trumpet does not sound until the end. The witness tarries and delays, but it surely comes! Psalm 3 begins with a cry of despair, yet ends with the confession of trust: "Deliverance belongs to the Lord." With still other psalms, the witness comes in the middle. In Psalm 23, the poet confesses, "you are with me." Or in Psalm 8, "you have made [human beings] a little lower than God."
The twin concepts of context and central theological witness go hand-in-hand. The two form both an interpretive strategy and a homiletic strategy. As an interpretive strategy, paying attention to context helps one to hear the witness of a psalm with integrity. Theology is not confessing one's faith. And all confession takes place in context. Whenever theologians have tried to reduce the faith to disembodied tenets (or fundamentals) that one can memorize, the words become sterile, denatured. But in context, such words speak with a driving force.
As a homiletic strategy, the twin concepts of context and witness suggest that in order to proclaim the central theological witness of a psalm, a preacher also has to flesh out for a congregation the context of the psalm. The preacher has to evoke for listeners the darkness of Psalm 23's valley, the watery peril of Psalm 130's depths, and the celebrating trumpets of Psalm 150. When the faithful can see, hear and feel those contexts, they will also have ears to hear the witness of the psalms.