Let's suppose you just heard something that a person has said about another person. Without examining whether it is true or not, you might just believe that it is true and possibly misunderstand and judge others. You can't know for certain what really happened. The speaker might have added his own feeling to the real story, or he might have told the story in a way that is beneficial to him. If so, then the true story may have changed. Therefore, a wise man doesn't carelessly judge others and he's not swayed when he hears rumors about the circumstances of others.