A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown [1882] at sacred-texts.com
Psalms Chapter 51
On the occasion, compare Sa2 11:12. The Psalm illustrates true repentance, in which are comprised conviction, confession, sorrow, prayer for mercy, and purposes of amendment, and it is accompanied by a lively faith. (Psa. 51:1-19)
A plea for mercy is a confession of guilt.
blot out--as from a register.
transgressions--literally, "rebellions" (Psa 19:13; Psa 32:1).
Wash me--Purity as well as pardon is desired by true penitents.
For . . . before me--Conviction precedes forgiveness; and, as a gift of God, is a plea for it (Sa2 12:13; Psa 32:5; Jo1 1:9).
Against thee--chiefly, and as sins against others are violations of God's law, in one sense only.
that . . . judgest--that is, all palliation of his crime is excluded; it is the design in making this confession to recognize God's justice, however severe the sentence.
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.
thou shalt make, &c.--may be taken to express God's gracious purpose in view of His strict requisition; a purpose of which David might have availed himself as a check to his native love for sin, and, in not doing so, aggravated his guilt.
truth . . . and . . .wisdom--are terms often used for piety (compare Job 28:28; Psa 119:30).
A series of prayers for forgiveness and purifying.
Purge . . . hyssop--The use of this plant in the ritual (Exo 12:22; Num 19:6, Num 19:18) suggests the idea of atonement as prominent here; "purge" refers to vicarious satisfaction (Num 19:17-20).
Make . . . joy--by forgiving me, which will change distress to joy.
Hide, &c.--Turn from beholding.
Create--a work of almighty power.
in me--literally, "to me," or, "for me"; bestow as a gift, a heart free from taint of sin (Psa 24:4; Psa 73:1).
renew--implies that he had possessed it; the essential principle of a new nature had not been lost, but its influence interrupted (Luk 22:32); for Psa 51:11 shows that he had not lost God's presence and Spirit (Sa1 16:13), though he had lost the "joy of his salvation" (Psa 51:12), for whose return he prays.
right spirit--literally, "constant," "firm," not yielding to temptation.
free spirit--"thy" ought not to be supplied, for the word "free" is, literally, "willing," and "spirit" is that of David. "Let a willing spirit uphold me," that is, with a soul willingly conformed to God's law, he would be preserved in a right course of conduct.
Then--Such will be the effect of this gracious work.
ways--of providence and human duty (Psa 18:21, Psa 18:30; Psa 32:8; Luk 22:32).
Deliver--or, "Free me" (Psa 39:8) from the guilt of murder (Sa2 12:9-10; Psa 5:6).
righteousness--as in Psa 7:17; Psa 31:1.
open . . . lips--by removing my sense of guilt.
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.
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.
God reconciled, material sacrifices will be acceptable (Psa 4:5; compare Isa 1:11-17).