How do we know the doctrine of a clear conscience is true?

The truth of the doctrine regarding a clear conscience is rooted in biblical teaching. Hebrews 9:14 expresses that the blood of Christ purges our consciences from dead works so we can serve the living God. This indicates that it's not through our efforts or good works that we achieve a clear conscience, but through Christ's redemptive work. Paul also highlights the importance of sincere ministry and honest conduct as crucial components of maintaining a clear conscience, thus supporting this doctrine through both personal testimony and the teachings of Scripture.