Ps. 51.4b (more an object of judgment, more an object of mercy)

And so /you are in the right / when you speak
and blameless / in giving judgment. 

From the act of confession David now turns to the act of judgment. David has acknowledged his sin, taken ownership over it, and allowed it to penetrate him deeply. He has, in that depth, come to see that his rebellion has sunk just as deep within God. It is important to see how this act of possession, of taking to himself the guilt of his rebellion, is itself a type of cleansing or purgation by way of exposure. David is, in a sense, getting completely out of the way of God’s judgment precisely in the act of utterly consuming his own guilt in his rebellion. In a way, he is allowing his rebellion to ‘fill him up’ such that he makes of himself a perfect object of judgment. What we see in this is David is consistently removing, by accepting of his fault, any trace of rebellion within himself. He is allowing his guilt to wash over him, to penetrate him and to ‘fill him up’. Once this is done, he then places himself in front of God as a perfect demonstration of what can be judged by God. He will not fight back; he will not do now what he did before: rebel. This sense of total ownership creates the sense of total exposure to God. This is the sense captured in these lines—the sense that God is, without question, and without remainder, utterly and completely justified in speaking and judging David. And it is at this point—at the perfect intensity of his exposure to God’s judgment—that we find David turn now from appealing to God’s mercy (vs. 1) and submitting to the fully justified wrath of God. These twin understandings are not at odds with each other. The more fully David exposes himself to God in judgment the more he is simultaneously appealing to God’s “abundant mercy”. Indeed, we might say this: the more one exposes oneself, fully perfecting in oneself the exposure of one’s sin, the more one will come to see in God an utterly justified act of judgment; and, from that position one can, within the covenantal structure, appeal to God’s abundant mercy. The more David makes himself to be an object of judgment the more he is making himself to be an object of mercy. The more David makes himself out to be an object of shattering, the more he makes himself out to be an object of re-creation.