What is the wisdom behind a person seeking treatment through medicine and the Qur'an when ill, despite Allah's ability to heal with "Be, and it is"?

Allah is All-Wise and All-Knowing; He decrees nothing except for a wisdom, whether apparent or not. Sickness contains great wisdoms and secrets, among them is the servant's feeling of his weakness and his need for Allah, and his submission to Him. The ordainment of means for healing, such as ruqyah and doctors, is a manifestation of His mercy, so that He may show His servants His kindness and benevolence. He also tests His servants in their good opinion of Him and their reliance on Him, so they utilize the means while their hearts remain attached to Him, Exalted be He.