Psalm 51 is David’s prayer of repentance after the Bathsheba and Uriah incident. It’s probably the best-known prayer of repentance in the Bible, the words of a man who realizes that his life has not turned out the way he hoped it would, that he isn’t the man he thought he was, he isn’t the “pretty alright guy more or less” that he’d told himself he was. It’s the prayer of a man who has blown through any possibility of denial and is face to face with every bit of the horror and ugliness of sin.
This moment of sorrow and tears is a great one for David, the moment when things stop spiraling downward and begin to turn, the moment of repentance. He realizes that what he wants most of all is the opposite of what he’s been pursuing. What he wants most of all is a pure heart, a faithful spirit, and the innocent joy of the presence of God.