Psalm 19:12

Who among us really knows how much we sin? Who is really aware of how vile we are? Who even knows all the sins he has committed or are in the process of committing? Who knows how defiled we are by our flesh? How strong human nature is in us still—after who knows how many years of being in the church? So David says, "Cleanse me from the faults that I don't know about, others don't know about, that I've hidden from myself, that I didn't even know were sin."

Richard T. Ritenbaugh
Presumptuousness

Psalm 19:12-13

Secret faults are sins that we commit that we do not see or recognize as sins. We commit them not knowing we have committed sin. Nevertheless, we are still held accountable for our actions, and we will eventually pay the penalty. Ignorance of the law is no excuse. Presumptuous sins are willful sins, ones we do knowing that they are sin before we commit them. Such willful sins, depending on one's attitude, can be spiritually very dangerous.

The godly man is not only concerned about avoiding committing sins willfully, but also with extracting those hidden sins that are committed unknowingly. Because we so often allow our carnal natures to dominate us, we remain blind to many of our sins and character flaws until God reveals them to us through the Holy Spirit.

Martin G. Collins
Comparing Ourselves Among Ourselves