Psalms 19:13

Keep back, or restrain, or withdraw; which word is emphatical, and signifies man's natural and great proneness even to the worst of sins, and the necessity of God's grace, as a bridle, to keep men from rushing upon them. Having begged pardon for his former errors, he now begs grace to keep him from relapses for the time to come. From presumptuous sins; from known and evident sins, such as are committed against knowledge and deliberation with design, and resolution, and eagerness, with resistance against the checks of conscience, and the motions of God's Spirit, and with contempt both of God's commands and judgments, and so with pride and insolency, which this word signifies. See Exodus 21:14. And such a sin was that of David's in the matter of Uriah, to which he seems to have an eye, and prayeth to be kept from such miscarriages. Let them not have dominion over me; if I be at any time tempted to any such sins, Lord, let them not prevail over me; and if I do fall into them, let me speedily rise again, and not willingly give up myself to the customary practice of them. Then shall I be upright; that will be an evidence of my sincerity, and I shall have this comfort, that although I am not absolutely perfect, but encompassed with many infirmities, yet I am an upright person, and such as thou wilt accept. I shall be innocent; thou wilt hold me for innocent. Or, I shall be cleansed, or kept pure, as this word primarily signifies. From the great transgression, i.e. from the guilt of such presumptuous sins, which are indeed very great transgressions, and such as, if accompanied with obstinacy and impenitency, thou wilt not pardon. But as for other sins of ignorance or infirmity, thou wilt graciously remit them for thy covenant's sake, made with me in and through thy Christ. Otherwise, from much transgression, or from innumerable sins, which usually follow the commission of one presumptuous sin, as David found by his own sad experience.