A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
psa 32:1Maschil--literally, "giving instruction." The Psalmist describes the blessings of His forgiveness, succeeding the pains of conviction, and deduces from his own experience instruction and exhortation to others. (Psa 32:1-11)
(Compare Rom 4:6).
forgiven--literally, "taken away," opposed to retain (Joh 20:23).
covered--so that God no longer regards the sin (Psa 85:3).
psa 32:2imputeth--charge to him, and treat him accordingly.
no guile--or, deceit, no false estimate of himself, nor insincerity before God (compare Rom 8:1).
psa 32:3A vivid description of felt, but unacknowledged, sin.
When--literally, "for," as in Psa 32:4.
psa 32:4thy hand--of God, or power in distressing him (Psa 38:2).
moisture--vital juices of the body, the parching heat of which expresses the anguish of the soul. On the other figures, compare Psa 6:2, Psa 6:7; Psa 31:9-11. If composed on the occasion of the fifty-first Psalm, this distress may have been protracted for several months.
psa 32:5A prompt fulfilment of the purposed confession is followed by a prompt forgiveness.
psa 32:6For this--that is, my happy experience.
godly--pious in the sense of Psa 4:3.
a time-- (Isa 55:6); when God's Spirit inclines us to seek pardon, He is ready to forgive.
floods, &c.--denotes great danger (Psa 18:17; Psa 66:12).
psa 32:7His experience illustrates the statement of Psa 32:6.
psa 32:8Whether, as most likely, the language of David (compare Psa 51:13), or that of God, this is a promise of divine guidance.
I will . . . mine eye--or, My eye shall be on thee, watching and directing thy way.
psa 32:9The latter clause, more literally, "in that they come not near thee"; that is, because they will not come, &c., unless forced by bit and bridle.
psa 32:10The sorrows of the impenitent contrasted with the peace and safety secured by God's mercy.
psa 32:11The righteous and upright, or those conforming to the divine teaching for securing the divine blessing, may well rejoice with shouting.