Jesus responded that the one that was without sin should cast the first stone at the woman. In v.9, we learn that the conscience of these Pharisees and Scribes was convicted. In the light of their sin being revealed, they realized they were sinners and one by one, they walked away.
Conviction of the conscience is only valuable if it is followed by action. When we are confronted by truths in God's Word that reveal our own sin and the need to repent and change, we ought to heed that warning. What if the Pharisees ignored the conviction of their conscience and stoned the woman anyway? We would observe their behavior and proclaim that they were very foolish and arrogant for ignoring the conviction of their own conscience. But do we have the same indignation toward ourselves when we ignore the conviction of our own conscience? How foolish we are if we should be confronted with the truth of our sin and need for Christ or our need to change and ignore it!
Jesus did not ignore the woman's sin either. Any kind of sexual activity outside of marriage is sin and Jesus makes no exception here - he tells the woman to "go and sin no more." Consider her plight: Under the law, she was condemned. But Jesus forgave her sin. How ungrateful she would be if she then returned to the same sinful life she was just delivered from! Let's heed the conviction of the conscience and appreciate the grace of God by living a life pleasing to the Lord.
