Have mercy upon me, O God, according to thy lovingkindness: according unto the multitude of thy tender mercies blot out my transgressions.
Nathan's rebuke roused David from a spiritual torpor into which he had sunk for a long time. Seeing the magnitude of his guilt, he turns to God's infinite mercy as his only ground for hope, knowing he deserves multiplied condemnation and might justly be cast off forever.
AI summary
Commenting on Psalm 51:1-19
Have mercy upon me, O God. He appeals at once to the mercy of God, even before he mentions his sin. The sight of mercy is good for eyes that are sore with penitential weeping. Pardon of sin must ever be an act of pure mercy, and therefore to that attribute the awakened sinner flies. "According to thy lovingkindness." Act, O Lord, like thyself; give mercy like thy mercy.
The title has reference to a very sad story, that of David's fall. But, though he fell, he was not utterly cast down, for God graciously upheld him and raised him up. 1. The sin which, in this psalm, he laments, was the folly and wickedness he committed with his neighbour's wife, a sin not to be spoken of, nor thought of, without detestation.
Commenting on Psalm 51:1-6