The Prophetic Medicine, by Al Hafiz Al-Maqdisi

"Allah has not sent a disease without sending a cure for it. The one who knows it knows it and the one who does not know does not know it. Narrated by Imam Aḥmad (3578) This is why the Messenger, may Allah's praise and blessings be upon him, enjoined to take care of himself, saying: "Servants of Allah, take care of yourselves, for Allah has not created a disease without creating its remedy, except for one. They said, "What is it?" He said, "Old age." Jāmi` At-Tirmidhī (2038)

Imam Ibn Al-Qayyim (d. 751 H.), may Allah have mercy on him, said about his speech, may the praises and greetings of Allah be upon him: “Every disease has a cure. “This strengthens the patient, as well as the doctor, and encourages them to seek this treatment ardently. When the soul of the sick feels that there is a cure that would dispel his disease, it increases the hope in his heart and cools the heat of despair, opening the door of hope to him. When the soul strengthens, its instinctive warmth is expressed, which is a cause for strengthening the animal, vegetable and natural spirits. When these souls grow stronger, grows stronger what drives them to this. Thus, they take over the disease and repel it. Likewise, if the doctor knows that this disease has a cure, he will be able to seek it earnestly. Diseases of the body are like diseases of the heart. Allah has not sent disease affecting hearts, without sending remedy against it. If the one taking the treatment knows this and uses it, and it coincides with the ailment of his heart, he will recover, by Allah's permission." Zād al-ma`ād (4/17)

The scholars have grouped what has been narrated from the Messenger, may Allah's praise and blessings be upon him, among the hadiths relating to medicine in all its forms, devoting chapters to them in their works. And they also devoted independent works to medicine, entitled "The Prophetic Medicine". Among them is that book which is in your hands, of the Imam and Ḥāfiẓ Ḍiyā' ad-dīn Abū ʻAbdillāh Muḥammad ibn ʻAbd Al-Waḥid as-Saʻdī al-Maqdisī (d. 643 H.), of which Allah is asked may He make it profitable.