Malik related to me that he heard that Umar ibn al-Khattab wanted
to go to Iraq, and Kabal-Ahbar said to him, "Do not go there, amir al-
muminin. There is nine-tenths of sorcery there and it is the place of
the rebellious jinn and the disease which the doctors are unable to
cure."
Muwatta Malik Book 54, Hadith 30