Taken from the book called "Healing with the Medicine of the Prophet (sallAllaahu alaihi wa sallam) by Ibn Qayyim al-Jauziyah on pg. 24

The hearts that are connected with the Lord of the Worlds - the Creator of the illness and its cure and He Who governs the affairs of everything and everyone - require special types of remedies that are nothing like those required for the hearts that are far away from their Lord. Furthermore, whenever the soul and the heart become stronger (spiritually), they will cooperate to defeat the illness. How can anyone deny that the most effective cure for the ailment that afflicts the heart and soul occurs by feeling delight and joy when drawing closer to the Lord, loving Him, remembering Him, being totally dedicated and attentive to Him, depending on Him and seeking His help? Only the most ignorant people deny these facts, especially those who have the dullest intellect, the worst comprehension and who are the farthest from Allaah, and from knowing the true reality of mankind.