Is it necessary to seek absolution from someone who was slandered or cursed in one's heart, or whose misfortune was rejoiced over without any verbal or physical harm, given sincere repentance and deep remorse, or is this a right of Allah, for which repentance to Him suffices?

A Muslim does not rejoice in evil befalling his Muslim brother, nor does he gloat over him, for the Prophet, peace and blessings be upon him, said: "None of you believes until he loves for his brother what he loves for himself." Backbiting and reviling in the heart are forgiven as long as the tongue does not utter them or one does not act in a way that indicates them, and the Prophet, peace and blessings be upon him, said: "Indeed, Allah has forgiven my Ummah for what they whisper to themselves, as long as they do not act upon it or speak of it."

Backbiting that is religiously recognized (as a sin) requires repentance. There is a difference of opinion regarding repentance from it: Is it sufficient to fulfill the three conditions of repentance, or is it necessary to seek absolution from the one who was backbitten?

The first opinion: It is necessary to seek absolution from the one who was backbitten, if possible, by asking for pardon and forgiveness. If it is not possible, then one should seek forgiveness for him and mention him in a good light.

The second opinion: It is not necessary to seek absolution. Rather, it is sufficient to seek forgiveness and mention him in a good light among people. It is preferable not to inform him due to the potential harms that may result, and this is the choice of Shaykh al-Islam Ibn Taymiyyah.

The third opinion (which is the preferred one): If the one who was backbitten knows about it, then it is necessary to seek his absolution. If he does not know, then it is sufficient to seek forgiveness for him and praise him in the gatherings where he was backbitten.