The placement of this verse in David’s prayer is significant. One would have expected such statements to come on the heels of his earlier statements of contrition found in the first four verses. It would make sense to hear about “the joy of salvation” (vs. 12), teaching transgressors the ways of God (vs. 13) and joyfully singing about God’s righteousness (vs. 14) after all the business of repentance had been dispensed with.
But if there is one thing that stands out throughout this psalm it is that David is thinking about the long term aspects of his relationship with the Lord. When he asks to be thoroughly cleansed of his iniquity (vs. 2), purified with hyssop (vs. 7), given a steadfast spirit (vs. 10) and promises to teach transgressors (vs. 13), he is showing that he is making a long term commitment to remain faithful to God.
Many people offer up a superficial prayer of repentance and cannot seem to “move on” quickly enough. It is as if they want to put as much distance as possible between themselves and the sense of brokenness and humility they have just experienced. But what is the point of repentance if it doesn’t accomplish the kind of heart change that will prevent the sins from happening again?
Repentance was never meant to be a one act show; it is supposed to be a regular facet of the new life one has entered into. The truth is that sincere believers are never very far from tears. How can they be, when every time they look within, they see the depravity of their own natures?
In the first four verses of Psalm 51, David thoroughly repented of the sins he had committed. I’m sure that if he would have stopped there God would have still been very pleased with the sincerity and intensity of his penitence. But David no sooner begins to feel the relief of the burden of guilt and the joy of his salvation, then he returns to his penitential posture. In other words, he saw brokenness over his sinful nature as something that would become an integral part of his future life.