What does the Bible say about purging the conscience?

In Hebrews 9:14, it is stated that the blood of Christ, offered through the eternal Spirit, has the power to purge our conscience from dead works so that we may serve the living God. This highlights the inadequacy of ceremonial laws and sacrifices to truly cleanse one's guilt. While various religious practices may attempt to address guilt, they ultimately fall short; it is only through the sacrificial work of Christ that individuals can attain a clear and purged conscience. Attempts to cleanse oneself through personal effort are deemed inadequate, echoing the sentiment that self-righteousness cannot lead one to salvation.