Sheikh Sa`ûd al-Funaysân, former professor at al-Imâm University
The person who backbites others and damages their reputations should be confronted and advised. It would be best if this advice is given discretely and in secret, since this is more desirable and usually proves more likely to be accepted.
If this person, after being advised discretely on two or three occasions, refuses to heed this advice, then the advisor may mention that person’s name and behavior to those people whom he has backbitten.
The evidence for this is that Allah says: “Allah does not love the public utterance of hurtful speech unless (it be) by one to whom injustice has been done.” [Sûrah al-Nisâ’: 148]
The person to whom injustice has been done, in turn, has a right against the ill-speaker. He may speak out against him and mention that which is injurious to the backbiter. However, he should not exceed that.
The people who engage in backbiting should know that they deserve a severe punishment for their sin.
Allah says: “And those who speak evil things of the believing men and the believing women without their having earned (it), they are guilty indeed of a false accusation and a manifest sin.” [Sûrah al-Ahzâb: 58]
The Prophet (peace be upon him) said: “A man might speak a word without thinking about its implications, but because of it, he will plunge into the Hellfire further than the distance between the east and west.” [Sahîh al-Bukhârî (6477) and Sahîh Muslim (2988)]
And Allah knows best.
Source: Islam Today