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

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.