In The Name of Allaah, The Most Merciful, The Bestower of Mercy
Imaam As-Sadi [rahimahullaah] said:
And among the beneficial affairs is to know that the harm of the people against you- especially evil speech- does not harm you; rather it harms them, unless you preoccupy yourself by giving it importance and [thus] it dominates your emotions, then it will harm you as it harms them. Indeed, it will not harm you in anyway if you pay no attention to it.
[Source: (Al-Wasaa-il Al-Mufeedah: page:30). abridged and slightly paraphrased]