Musnad Abu Ya'la al-Mawsili 109:38

Harun ibn Ma'ruf narrated to us, Abdullah ibn Wahb narrated to us, he said: Amr ibn al-Harith informed me that Bukayr narrated to him that Asim ibn Umar ibn Qatadah narrated to him that Jabir ibn Abdullah visited al-Muqanna', then he said: I will not depart until you are cupped, for I heard the Messenger of Allah, may Allah bless him and grant him peace, saying: "Indeed, there is a cure in it."