Abu Dawud Book 36, Hadith Number 4860.
Chapter : Not known.
Narated By Anas ibn Malik : The Prophet (PBUH) said: When I was taken up to heaven I passed by people who had nails of copper and were scratching their faces and their breasts. I said: Who are these people, Gabriel? He replied: They are those who were given to back biting and who aspersed people’s honour.