Al-Harith bin Sa'd narrates from his father, Sayyiduna Sa'd (may Allah be pleased with him), who said: I said: O Messenger of Allah, the incantations (ruqyah) we use and the medicines we use for treatment, do you think they can avert the decree of Allah? He (peace and blessings be upon him) said: "They too are part of the decree of Allah." (Imam al-Tabarani said:) Uthman bin Umar narrated it like this from Yunus, and other people differed with him and narrated it from Yunus in the same way that people narrated it from al-Zuhri, from Abu Khuzamah.
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5449