Prophet Mohammad (PBUH) said:
Do you know what backbiting is? They answered: Allah and His Prophet know more. He said: It is talking about your brother what he hates. They said: What if what I am saying truly exists in him? The Prophet said: If it exists then you have backbit him, and if it was false then unpleasant or cruel talk about someone who is not present then you have slandered him.
At-Targhib wat-Tarhib, vol 3, p 515
