What Is the Expiation for Backbiting?

Backbiting means you have spoken about someone in their absence and criticised them in front of other people. The scholars differed about this, some of them said you must go to the one you spoke about and say, "I spoke bad about you to the people, I hope you can forgive me and pardon me," and some scholars said: no, don’t go to him; rather there are more details. So, if the person knows about this backbiting, then you must go to him and ask him to forgive you, and if the person doesn’t know, then don’t go to him. Seek forgiveness for him; and speak about his good qualities in the gatherings in which you backbit him. Because certainly good deeds erase evil deeds. And this is the most correct view. Say, “O Allah forgive him." As mentioned in the Hadith that the expiation of the one you've backbitten is to seek forgiveness for him.