One of the actions severely prohibited in Islam is backbiting. Backbiting is to narrate and display a deficiency or the negative action of (believing person, which he would not like to be disclosed. On the other hand, to disclose something, which is evident, which the doer himself does not hide is not forbidden. Also if an oppressed person narrates about the oppressive actions of his oppressor or if someone speaks about a person who has made an innovation in religion, it is not forbidden. There are other instances where narrating the negative qualities of someone is not forbidden and they are discussed in books of Islamic law. Listening to backbiting is also forbidden and the listener should defend the victim.
Allah the Most High said: “O you, who believe, avoid most of suspicion, for surely suspicion in some cases is a sin, and do not spy nor let some of you back-bite others. Does one of you like to eat the flesh of his dead brother? Verily you abhor it; and be careful of (your duty to) Allah, surely Allah is Oft-returning (to mercy), Merciful.”
He also said: “Surely those who love that scandal should circulate respecting those who believe, they shall have a grievous chastisement in this world and the hereafter; and Allah knows, while you do not know.”
The Holy Prophet Muhammad (S) said: “Backbiting is worse than fornication.” He was asked: “O Messenger of Allah, why is it so?” He (S) replied: “The fornicator may repent and Allah accept his repentance; but although the backbiter may repent, Allah will never accept his repentance until his victim pardons him.”
He (S) also said: “I swear by Allah besides Whom there is no god, that no believer can ever attain the benefits of this world and the world to come except by his good opinion of Allah, hope, good nature and abstaining from backbiting of the believers. I swear by Allah besides Whom there is no god, that no repenting believer will be punished except for his suspicion about Allah, despair, ill nature and backbiting of the believers. I swear by Allah besides Whom there is no god, that no believing servant has a good opinion of Allah except He will behave duly towards His believing servant. For Allah is generous and graceful, When His believing servant has a good opinion of Him, He does not fail to do according to it. So have a good opinion of Allah and wish for Him.”
Imam Ja’far al-Sadiq (a.s.) said: “Anyone who narrates about a believer what his eyes have seen and his ears have heard, he is of those about whom Allah has said: ‘Surely those who love that scandal should circulate respecting those who believe, they shall have a grievous chastisement in this world and the hereafter.’”