Here we need statements like those which the holy fathers undoubtedly used to ponder a great deal. Though He is talking there about physical blessing, the Lord says in Deuteronomy 9:5 “Not because of your righteousness or the uprightness of your heart are you going in to possess the land of the nations.” Again (Is. 43:25): I am the Lord, who blots out your transgressions.” Again (Ezek. 33:11): “I do not want the death of the sinner.” Here we also need some examples. When the people of Nineveh do penance, that is, when they are humbled in the acknowledgment of their sin, God retracts His sentence and says (Jonah 3:10): “I shall not destroy them.” In the same way He forgives Ahab, whom He had threatened with destruction of his family, and says to the prophet (1 Kings 21:29): “Have you seen how Ahab has humbled himself before Me?” From these histories there arises this theological knowledge of God: that God is the God of the humble, the afflicted, and the poor who acknowledge that they are sinners and fear God in such a way that they hope still more in His mercy. The holy fathers in the Old Testament undoubtedly knew such statements and examples very well and held them very dear.
Martin Luther commenting on Psalm 51:3
Luther’s Works v. 12 333-334