That is a classic quote from Epictetus pondered in a post by the same title from Philosiblog.
The simpler cousin of that comment is the concept that if you receive criticism, you ought to evaluate which parts are correct and make the appropriate changes. You are free to ignore those parts of the criticism which are invalid.
When the comment about you involves lies, the above quote suggests you evaluate whether there is any truth in the comments. If so, then you have some work to do.
The difficult part is when the evil spoken of you is a lie.