Musnad Ahmad 1153:929

Muhammad ibn Ja'far narrated to us, he said: Shu'bah narrated to us, from Sulayman, from Abu al-Duha, from Masruq, from 'Aishah, that the Prophet, peace and blessings of Allah be upon him, when he would visit a sick person, he would wipe him with his hand and say: "Remove the harm, O Lord of the people, and heal, for You are the Healer. There is no healing but Your healing, a healing that leaves behind no illness." When he fell ill with the illness in which he died, 'Aishah said: I took his hand, and I went to say [the supplication], but he pulled his hand away and said: "O Allah, forgive me, and place me with the Highest Companion."