Blessed is he whose transgression is forgiven, Whose sin is covered. Blessed is the man to whom the LORD does not impute iniquity, And in whose spirit there is no deceit. (Psalm 32:1-2)
This psalm of David expresses the joy of forgiveness. Luther sought a merciful God and found Him. A God where he may receive forgiveness. However the forgiveness cost the life of God's only beloved Son. It is His blood, that covers our sin. It is His blood that cleanse a deceitful or a hypocritical soul, and to regenerate a person in His image with a spirit in whom there are no deceit.