He Called It Sin
  Jesus did not dismiss the adultery of which a woman was guilty as minor. Unlike those who were accusing her, He had interest in her spiritual welfare. That meant she had to be forgiven of her sin. Her accusers were correct in labeling her action as despicable, but they did not seek her salvation but condemnation and to display their self-righteousness.

  Jesus obviously forgave her rather than condemning her. Without forgiveness she stood condemned. Forgiven she was not condemned. But she had the obligation to "go and sin no more." None can doubt Jesus considered her behavior sinful. But she wasn't the only sinner He confronted that day. He forgave her sin. Her accusers convicted themselves.