Musnad Ahmad 33:482

Harun ibn Ma'ruf narrated to us, Ibn Wahb narrated to us, 'Amr ibn al-Harith narrated to us, from 'Abd Rabbih ibn Sa'id, from Abu al-Zubayr, from Jabir, from the Prophet, peace and blessings of Allah be upon him, that he said: "For every disease there is a cure. So when the cure for the disease is attained, it heals by the permission of Allah the Exalted."