Have mercy on me, O God, according to your steadfast love; according to your abundant mercy blot out my transgressions. (Psalm 51:1)

Three times: “Have mercy,” “according to your steadfast love,” and “according to your abundant mercy.”

This is what God had promised in Exodus 34:6–7:

“The Lord, the Lord, a God merciful and gracious, slow to anger, and abounding in steadfast love and faithfulness, keeping steadfast love for thousands, forgiving iniquity and transgression and sin, but who will by no means clear the guilty.”

David knew that there were guilty who would not be forgiven. And there were guilty who by some mysterious work of redemption would not be counted as guilty, but would be forgiven. Psalm 51 is his way of laying hold on that mystery of mercy.

“Have mercy on me, O God, according to your steadfast love; according to your abundant mercy blot out my transgressions.” We know more of the mystery of this redemption than David did. We know Christ. But we lay hold of the mercy in the same way he did.

The decisive thing he does is turn, helpless, to the mercy and love of God. Today that means turning, helpless, to Christ, whose blood secures all the mercy we need.