How do we know that God's law exposes sin?

The law of God is primarily given to expose sin, as stated in Romans 3:20, which teaches that through the law comes the knowledge of sin. The law serves to show us our shortcomings, proving that we are guilty before God and unable to achieve righteousness through our own efforts. Paul further elaborates on this in Romans 7:7, where he reveals that he had not known sin except through the law. The law acts as a mirror, reflecting our sinful nature and our need for a Savior, ultimately demonstrating our complete reliance on God's grace.