Psalms 51 — Jamieson–Fausset–Brown
51:1–4
1-4. A plea for mercy is a confession of guilt. blot out--as from a register. transgressions--literally, "rebellions" (Psa 19:13; 32:1).
51:5–6
5-6. His guilt was aggravated by his essential, native sinfulness, which is as contrary to God's requisitions of inward purity as are outward sins to those for right conduct.
51:7–12
7-12. A series of prayers for forgiveness and purifying. Purge ... hyssop--The use of this plant in the ritual (Ex 12:22; Nu 19:6, 18) suggests the idea of atonement as prominent here; "purge" refers to vicarious satisfaction (Nu 19:17-20).
51:13
13. Then--Such will be the effect of this gracious work. ways--of providence and human duty (Psa 18:21, 30; 32:8; Lu 22:32).
51:14
14. Deliver--or, "Free me" (Psa 39:8) from the guilt of murder (2Sa 12:9, 10; Psa 5:6). righteousness--as in Psa 7:17; 31:1.
51:15
15. open ... lips--by removing my sense of guilt.
51:16
16. Praise is better than sacrifice (Psa 50:14), and implying faith, penitence, and love, glorifies God. In true penitents the joys of pardon mingle with sorrow for sin.
51:18
18. Do good, c.--Visit not my sin on Thy Church. build ... walls--is to show favor; compare Psa 89:40, for opposite form and idea.
51:19
19. God reconciled, material sacrifices will be acceptable (Psa 4:5; compare Is 1:11-17).