Praise be to Allah.
The correct view –and Allah knows best – is that he should not tell him that he has gossiped about him if he does not know; it is sufficient just to ask Allah for forgiveness for the sin and to ask for forgiveness for his brother to counteract the harm caused by his gossiping about him.
There follow some of the scholars’ opinions on this matter:
Al-Nawawi (may Allah have mecy on him) said in his book al-Adhkar: “Know that everyone who commits a sin must hasten to repent from it. Repentance in the case of a sin involving the rights of Allah (i.e., in which no other person is affected) requires the following three conditions:
He must give up the sin immediately
He must regret what he has done
He must resolve not to do it again.
With regard to repentance from a sin that affects the rights of other people, these three conditions are also required, and to them is added a fourth: he must restore to people what is due to them and settle the matter, or else ask for forgiveness and find a way to relieve himself of this burden of sin.
The repentance of the backbiter must meet these four conditions, because backbiting or gossip affects other people, so he has to seek the forgiveness of the person about whom he gossiped.
Is it sufficient for him to say: ‘I gossiped about you so please forgive me’, or does he have to tell him what he said about him?
The companions of al-Shafi’i (may Allah have mercy on them) had two views:
The first was that he has to tell him, because if he forgives him without being told what was said, it does not count, as in the case of forgiving someone with regard to an unknown amount of money.
The second was that he does not have to tell him, because this is something that can be forgiven, so he does not have to tell him what he said, unlike the case with money.
The first view is more correct, because a person could forgive some type of gossip but not others.
If the person about whom you gossiped is dead or is not present, it is not possible to ask him for forgiveness, but the scholars said: you should pray a lot for him to be forgiven, and make du’a (supplicate) for him, and do lots of good deeds.
Know that the person who was spoken about should forgive him for that, but he does not have to, because this is a voluntary giving up of one's rights. The choice is up to him, but it is strongly encouraged (mustahab) for him to forgive him, so that his Muslim brother may be relieved of the consequences of his sin and he himself may attain a great reward from Allah and the love of Allah. (This was the view of al-Shafi’i)
Ibn Muflih said in al-Adab al-Shara’iyyah: “It was said that if the person who was wronged by the gossip knows about it (then you cannot do anything about that), otherwise you should make du’a for him and pray for forgiveness, but he should not be told. Shaykh Taqiy al-Deen mentioned that this was the view of the majority.
More than one scholar said: if a person who slandered or gossiped about another repents before the person comes to know about it, is it a condition of his repentance that he should tell the person and ask for his forgiveness? There are two views.
Al-Qadi said that he does not have to do that, because of the reports narrated by Abu Muhammad al-Khallal with his isnad (chain of narration) from Anas, and attributed to the Prophet (peace and blessings of Allah be upon him): “Whoever backbites about a man then asks for forgiveness for him, his backbiting will be forgiven” and “The kafarah (expiation) of the one who gossips about another is that he should ask for forgiveness for him.” These two ahadeeth (reports) are not saheeh (authentic) in their transmission from the Prophet (peace and blessings of Allah be upon him). Another reason is that by telling the person what was said, this may make him hate him. Al-Qadi said: this is not permissible. This was also the view of Shaykh Abd al-Qadir.
Ibn ‘Abd al-Barr said in his book Bahjat al-Majalis: “Hudhayfah (may Allah be pleased with him) said: The kafarah (expiation) of the one who gossips about another is that he should ask for forgiveness for him.” ‘Abd-Allah ibn al-Mubarak said to Sufyaan ibn ‘Uyaynah: the repentance for backbiting is that you should pray for forgiveness for the one you gossiped about. Sufyan said: rather you should ask for forgiveness for what you said about him. Ibn al-Mubarak said: do not hurt him twice. Shaykh Taqiy al-Deen ibn al-Salah al-Shafi’i also said in his Fatawa something like that which was said by Ibn al-Mubarak.
After mentioning these two reports on this issue, Shaykh Taqiy al-Deen said: “Any talk about a person’s honour is either truthful gossip or a fabricated lie. In either case it is slander, because if slander is true then it is gossip and if it is not true then it is a false accusation.”
Our companions were of the opinion that he should not tell him; rather he should make du’a for him which will be a good deed towards him, to make up for his wrongdoing towards him, as was stated in the reports.
It is clear that what Shaykh Taqiy al-Deen (may Allah have mercy on him) said about telling the person hurting him twice makes sense, and that there is the fear that it could lead to conflict, hatred and a breakdown of the relationship between them.
And Allah knows best.