It is not likely that we shall be kept from the great transgression unless we are preserved from presumptuous sins; and these in turn will befall us unless we have been cleansed from bidden faults. Just as the germ of disease taken into the system will presently reveal itself in an outburst of malignant fever, so hidden faults flower out into presumptuous sins, and these into great transgression. "Then lust, when it hath conceived, beareth sin; and the sin, when it full-grown bringeth forth death."
First, we need forgiveness for secret sins. The Jewish law made large provision for sins of ignorance. A man might unawares walk across a grave, or touch some article of furniture which was ceremonially unclean, and so become defiled. Even though unconscious of actual transgression, he would find his communion with God broken. Thus, after the holiest day we have ever spent we need to ask for cleansing in the precious blood, for sins which God has discerned, but which in the twilight of our ignorance, and because we compared ourselves with those beneath us in spiritual attainment, have escaped notice.
Next, we need deliverance from the love and power of sin, in lower depths than we have ever realized. We desire to pass muster at the bar, not only of our neighbours and ourselves, but of God. We desire that the Spirit should antagonize the flesh in depths below the reach of the plumb-line of our consciousness. We desire the inner purity of heart. But this is peculiarly God's prerogative. It is his work to cleanse the thoughts of our hearts by the inspiration of his Holy Spirit. "Cleanse THOU me.