Jesus wants us to notice the plank in our own eye before seeing the speck in our brother's eye. And he asked whomever without sin to cast the first stone at the adulterous women caught in the act. St. Therese learned to never speak ill of anyone and only say the good things about a "bad" person. All these examples teach us not to judge others. Those who love to criticize others are unhappy people, because they fail to see that God loves everyone, including the critic.