Musnad Ahmad 1118:23

Abu al-Yaman narrated to us, he said: Abu Bakr—meaning Ibn Abi Maryam—narrated to us, from the elders, from Fadalah ibn Ubayd al-Ansari, who said: The Prophet, peace and blessings of Allah be upon him, taught me a ruqyah (incantation) and commanded me to perform it for whomever I wished. He said to me: "Say: 'Our Lord is Allah who is in the heavens, holy is Your name, Your command is in the heaven and the earth. O Allah, just as Your command is in the heaven, place Your mercy upon us on the earth. O Allah, Lord of the good, forgive us our sins, our transgressions, and our faults, and send down a mercy from Your mercy and a healing from Your healing upon whatever complaint so-and-so has, so that he may be healed.'" He said: "And say that three times, then seek refuge with the two surahs of seeking refuge (al-Mu'awwidhatayn) three times."