Maliks Muwatta Book 41, Hadith Number 17.

Section : The Hadd for Slander, Denial and Insinuation.

Malik related to me from Abu’z-Zinad that he said, ”Umar ibn Abd al-Aziz flogged a slave with eighty lashes for slander.”

Abu’z-Zinad said, “I asked Abdullah ibn Amir ibn Rabia about that. He said, ‘I saw Umar ibn al-Khattab, Uthman ibn Affan, the Khalifs, and so on, and I did not see any of them flog a slave more than forty lashes for slander.'”