David"s rhetorical question expresses the impossibility of knowing if or when we violate God"s will without the light that His Word provides. It can bring to light faults hidden otherwise and can warn us of what displeases God so we can confess and avoid these offenses. David asked God to use His Word to bring these sins to his attention so they would not dominate him. This would result in his being blameless in God"s sight and free from the huge mass of sin that would be his without the revelation of Scripture. [source][source][source]