Hadith: When I was taken on an ascent to heaven, I passed by a group of people (in Hellfire) with copper nails scratching their faces and chests

عَنْ أَنَسِ بْنِ مَالِكٍ رَضيَ اللهُ عنه قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ:
«لَمَّا عُرِجَ بِي مَرَرْتُ بِقَوْمٍ لَهُمْ أَظْفَارٌ مِنْ نُحَاسٍ يَخْمُشُونَ بها وُجُوهَهُمْ وَصُدُورَهُمْ، فَقُلْتُ: مَنْ هَؤُلَاءِ يَا جِبْرِيلُ، قَالَ: هَؤُلَاءِ الَّذِينَ يَأْكُلُونَ لُحُومَ النَّاسِ، وَيَقَعُونَ فِي أَعْرَاضِهِمْ».
[حسن] - [رواه أبو داود] - [سنن أبي داود: 4878]

Anas ibn Mālik (may Allah be pleased with him) reported: The Messenger of Allah (may Allah's peace and blessings be upon him) said:
"When I was taken on an ascent to heaven, I passed by a group of people (in Hellfire) with copper nails scratching their faces and chests. I asked: O Gabriel, who are these? He replied: These are the ones who eat the flesh of people (by backbiting) and slander them."
[Good hadith] - [Narrated by Abu Daoud - Narrated by Ahmad] - [Sunan Abu Daoud - 4878]

Explanation

The Prophet (may Allah's peace and blessings be upon him) informed that when he was taken up to the heavens on the night of Isrā’ and Mi‘rāj, he passed by a group of people who had nails of copper, with which they were scratching and tearing their own faces and chests. The Prophet (may Allah's peace and blessings be upon him) asked Jibrīl (Gabriel) (peace be upon him): What did these people do to deserve such punishment? Gabriel (peace be upon him) replied: They are those who used to backbite others and speak about people's honor unjustly.

Benefits from the Hadith

1. A stern warning against backbiting, with the backbiter likened to one who eats human flesh.
2. Violating people's honor through backbiting and similar acts is among the major sins.
3. At-Tībi, commenting on the Prophet's word "scratching”, said: Since scratching the face and chest is a trait of wailing women, it was made the punishment for those who backbite and slander Muslims—to indicate that such behavior is unbefitting of men and is instead from the traits of women in their most disgraceful and distorted state.
4. It is obligatory to believe in the unseen and in everything that Allah and His Messenger (may Allah's peace and blessings be upon him) have informed us of.