Our brothers and sisters in the faith before us have provided two important keys for unlocking this psalm.
First, there is the heading that says, "A Psalm of David, when the prophet Nathan came to him after he had gone in to Bathsheba." Supplied by the editors of the Book of Psalms, these headings often point the way to interpreting and applying the psalm. In this case, the heading is saying, "Imagine this as the sort of prayer that David prayed after being convicted of his sins by the prophet Nathan" (2 Samuel 11 and 12). We begin by recalling that story.
The story begins innocently enough: "In the spring of the year, the time when kings go forth to battle..." (2 Samuel 11:1). But this time the king is staying home. The one time slingshotting, swashbuckling, songwriting soldier is sitting this one out.
And then late one afternoon it happens. The old warrior is bored with the soaps and talk shows and takes a stroll out onto the veranda. But wait a minute! He notices a woman, a "very beautiful woman" says the Hebrew text, taking a dip in the pool next door.
Then the former man of action goes into action. A couple of calls gives him the woman's name and reveals that her husband is away with the army. The king sends for Bathsheba and she comes to the palace. They have a few gin and tonics. They make love. Then she goes home, and that's that.
A few months later, there's a message for the king. David opens the envelope and reads it. Two words in Hebrew: harah anoki. "I'm pregnant. Bathsheba" Again, the king acts. To account for the pregnancy he brings her husband back from the front. "Go home and sleep with your lovely wife," he says to him, slipping the soldier a bottle from the royal wine cellar. But Uriah refuses the offer and instead sleeps with the servants out on the lovely lawn.
The plot thickens and the story sickens. The king orders General Joab to put Uriah where the fighting is heaviest. Word comes that Uriah has been killed in action. The king does a magnanimous thing. He marries this broken-hearted war widow.
End of the story? Not quite. One day the prophet Nathan shows up at the palace. He tells the king about a rich man who has stolen a poor man's only lamb and slaughtered it for dinner. The king is enraged. "What? Who is this guy? Tell me, and we'll royally nail him!"
"You're the guy!" says Nathan. David is devastated. And this psalm, says our heading, is the sort of prayer that fits such a situation. When there's big time trouble, you call in Psalm 51.
In verses 1 -- 5, the psalm begins with a cry for forgiveness, emphasizing the urgency of the situation with a series of imperative verbs: have mercy, blot out, wash, and cleanse. The picture behind the Hebrew word translated "transgressions" in verses 1, 3, and 13, is one of rebellion, as when children rebel against parents (see also Isaiah 1:2). The literal sense of the Hebrew translated "iniquity" (verses 2, 9) is "to be bent out of shape." For example, in Psalm 38:6, the Jewish Publication Society Bible gives the translation "I am all bent." The word translated "sin" (Hebrew hata' in verses 2, 3, 4, 9) or "sinner" (5 and 13) in non-theological contexts means "to miss the target." Judges 20:16 tells of 700 left-handed sling-shotters who could "sling a stone at a hair and not miss (hata')."
Balancing these words for sin are three Hebrew picture-words for forgiveness. The Hebrew translated "blot out" in verse 1 is also used to "wipe" a dirty dish (2 Kings 21:13). To "wash" in verses 2 and 7 could better be translated "scrub," as one scrubs dirty clothes (Exodus 19:10, 14). "Cleanse" in verse 2 and "be clean" in verse 7 is the same word used for washing clothes in a river (Leviticus 13:6, 34, 58).
Verses 6 -- 12 offer another request for forgiveness. The verb "create" (verse 10) in the Hebrew Bible always has God as its subject, and the result of the activity is always something entirely new (see Genesis 1, for example). The psalmist is praying for a brand new beginning, a fresh start, a new, clean spirit.
In verses 13 -- 17, the one praying looks forward to being happy and right with God once again (verses 8, 11-12). Once he/she experiences the joy of being forgiven, he/she vows to witness and teach others about it and sing and praise God (verses 13-15). In verses 16 and 17 the psalmist says, "The sort of sacrifice the Lord desires is not something I bring as an offering. Rather, the Lord wants me, broken spirit, broken heart and all" (see also Micah 6:6-8).
Toward Counseling and Preaching: What Can You Do With a Broken Heart?
Every pastor knows that this is one of those psalms that can reach into the depths of a difficult situation. I recall a college student telling me about the sad breakup with his girlfriend. I suggested that he read through some of the psalms. The next week he showed up, bringing his Bible, with passages from the psalms marked in red. "These words were speaking right to me!" he said. Among the texts marked was Psalm 51: 17 about the broken heart.
I also remember listening as a man related an incredible story of his unfaithfulness and adultery. When we prayed together, it was Psalm 51 that I reached for.
Lastly, the second interpretive key from church tradition is the fact that this prayer, "Create in me a clean heart" from Psalm 51, has long been a part of the church's weekly worship. For example, in Evangelical Lutheran Worship, four hymn settings of verses 10-12 are available as options for each of ten worship settings (see ELW pages 106, 128 and hymns 185-188).
Thus Psalm 51 is a prayer for individuals in distress, but it is also a prayer for the community on Ash Wednesday and for the worship of God's People each week.