Charles H. Spurgeon on Psalms 32:5

I said, I will confess, etc. Justified persons, who have their sins forgiven, are yet bound to confess sin to God...There are many queries to be dispatched in the handling of this point. The first query is, what are the reasons why persons justified and pardoned are yet bound to make confession of sin unto God in private? The reasons are six. First, they are to confess sin unto God because holy confession gives a great deal of ease and holy quiet unto the mind of a sinner: concealed and indulged guilt contracts horror and dread on the conscience. Secondly, because God loves to hear the complaints and the confessions of his own people. Lying on the face is the best gesture, and the mourning weed the best garment that God is well pleased with. A third reason is, because confession of sin doth help to quicken the heart to strong and earnest supplication to God (see Ps 32:6). Confession is to the soul as the whetstone is to the knife, that sharpens it and puts an edge on it; so doth confession of sin. Confessing thy evils to God doth sharpen and put an edge on thy supplication; that man will pray but faintly that doth confess sin but slightly. A fourth reason is, because confession of sin will work a holy contrition and a godly sorrow in the heart. Ps 38:18. Declaration doth work compunction. Confession of sin is but the causing of sin to recoil on the conscience, which causeth blushing and shame of face, and grief of heart. A fifth reason is, because secret confession of sin doth give a great deal of glory to God. It gives glory to God's justice. I do confess sin, and do confess God in justice may damn me for my sin. It gives glory to God's mercy. I confess sin, yet mercy may save me. It gives glory to God's omniscience. In confessing sin I do acknowledge that God knoweth my sin. A sixth reason why justified persons must confess sin unto God is, because holy confession of sin will embitter sin, and endear Christ to them, when a man shall let sin recoil on his conscience, by a confession. Condensed from Christopher Love's "Soul's Cordial," 1683.