New Defender's Study Bible Notes
51:1 Have mercy upon me. Psalm 51 tells of David’s repentance, confession and plea for cleansing following Nathan’s rebuke after his sin with respect to Bathsheba and Uriah (II Samuel 12:1-15). Psalm 32 tells of his joy after God forgave him (Psalm 51:12).
51:7 hyssop. Hyssop was a small shrub used to sprinkle blood and water over the cleansed leper, symbolizing his purification and cleansing (Leviticus 14:4-7).