It is a fact that St. Teresa of Jesus was greatly slandered during her life. However, she never paid much attention to those calumnies, but rather was always grateful to those who persecuted her.
Once, she was accused of bringing women to her convent in order to corrupt them. When she was told this, she simply replied, “they do me a great favor; although I am not doing what they say, I have offended God very much and so one thing pays for the other.” In fact, the Bishop of Avila used to say: “if you want to be Mother Teresa’s best friend, all you need to do is one thing: bear false witness against her”.
In order to imitate her, we should work on the virtues of humility and charity. We need both virtues in order to do good to those who do something evil against us. This is one of the teachings that we find in Jesus’ words: To the person who strikes you on one cheek, offer the other one as well (Lk. 6:29). St. Paul also says something similar: do not return evil for evil; rather return good for evil (cf. 1 Th 5:15).
Our fallen nature wants to take revenge on those who offend us, hurt us, humiliate us, or, in short, do anything against us. In fact, there was an old law called the talion law: an eye for an eye and a tooth for a tooth (Mt. 5:38) that expresses this human desire of vengeance. Jesus replaced it with the law of charity.
Why do we need humility? Humility teaches us to put all of this in a different perspective. Humility helps us to admit that we really deserve nothing at all, and that everything that we think we deserve or do not deserve is, in the long run, dangerous for us. In the words of St. Paul, If I am to boast, I boast in the cross of our Lord Jesus Christ (Gal. 6:14). That is, I boast in being humiliated.
We also need to grow in charity. Charity never wants revenge, since charity can never want something bad for others. God is the source of charity, and He does not want/love evil nor does He cause it. Since charity comes from God, it always looks for ways to do good to others.