His father told him that he said to the Messenger of Allah ﷺ, "Messenger of Allah, what do you think of medicines we use for treatment, incantations we seek healing through, and protective measures we take? Do these things ward off anything from Allah's decree?"The Messenger of Allah ﷺ replied, "They themselves are part of Allah's decree."
أن أباه حدثه أنه قال الرسول الله ﷺ: يا رسول الله، أرأيت دواء نتداوي به، ورقي نشترقيها، وتقي نتقيها هل ترد ذلك من قدر الله من شيء؟ فقال رسول الله ﷺ: إنه من قدر الله.
Abdullah bin Wahb narrated it in Jami (699). He said, Yunus bin Yazid, Amr bin Harith, and Ibn Saman informed me, that Ibn Shihab informed them, that Abu Khuzama, then he mentioned it.Ahmad (15474) and Hakim (4/199) also reported it through the route of Ibn Wahb, except that Ahmad narrated it from him, from Amr bin Harith alone.This isnad is hasan, because no one narrated from Abu Khuzama except Zuhri, and he is a well known Tabi, whom Zuhri knew. Whoever counted him among the Companions erred, like Hafiz in Taqrib, who said, "A Companion, he has a hadith about incantations," when in fact the companionship belongs to his father.The hadith has other chains of transmission with Tirmidhi (3148, 2065), Ibn Majah (3437), and others, but what I have mentioned is the most sahih of them, and it is documented in the Book of Faith.