Musnad Ahmad 299:0

Narrated to us by Yahya ibn Sa’id, from Sufyan, who said: Narrated to us Habib ibn Abi Thabit, from ‘Amr ibn Wahb, from ‘Uthman ibn Abi al-‘As al-Thaqafi, that he complained to the Messenger of Allah (ﷺ) about a pain he had felt in his body since he embraced Islam. The Messenger of Allah (ﷺ) said to him: "Place your hand on the part of your body that hurts, and say: 'In the name of Allah' (Bismillah) three times, and say seven times: 'I seek refuge in the might of Allah and His power from the evil of what I find and what I guard against.'"