Silsilat al-Ahadith al-Sahihah

Sayyiduna Anas bin Malik (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "When my Lord took me on the Mi'raj (Ascension), I passed by some people whose fingernails were of copper, and they were scratching their faces and chests with them. I asked: 'Jibril! Who are these people?' He replied: 'These are the people who used to eat the flesh of others (i.e., backbite) and violate their honor.'"