Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrates that Sayyiduna Dimam bin Tha'labah (may Allah be pleased with him) came to the Messenger of Allah (peace and blessings be upon him) and said: O Muhammad, shall I not perform ruqyah (recite a cure) over you? The Prophet (peace and blessings be upon him) said: "All praise is for Allah; we praise Him and seek His help, and we seek refuge in Allah from the evils of our souls and the misdeeds of our actions. Whomever Allah guides, none can lead astray, and whomever He leads astray, none can guide. And I bear witness that there is no true god except Allah, and that Muhammad is His servant and Messenger." Dimam said: I have read the scriptures, the Torah, the Injil and the Zabur, but I have never heard anything like these words. Repeat them to me. So he (peace and blessings be upon him) repeated them. Then he said: Repeat them again. So he (peace and blessings be upon him) repeated them again. Then it was mentioned that he accepted Islam.
Hadith Referenceالمعجم الكبير للطبراني / باب الضاد / 8117