Muslim narrated in his Sahih that the Prophet a said:
“Every illness has a cure, and when the proper cure is applied to the disease, it ends it, Alläh willing.”
Also, it is narrated in the Sahihän that the Messenger of Alläh sa
“Alläh has not sent down a disease except that He has also sent down its cure.”
Further, Imam Ahmad narrated that Usamah b n Shuraik said:
“I was with the Prophet () when the Bedouins came to him and said, ‘O Messenger of AIIäh, should we seek medicine?’ He said,’Yes, O slaves of AIIäh, seek medicine, for AIIäh has not created a disease except that he has also created its cure, except for one illness.’ They said, ‘And what is that?’ He said, ‘Old age.
In addition,it is related in the Musnad (by Imam Ahmad) that the Prophet a said:
“AIIäh has not sent down a disease except that He also sent down its cure; whoever knows it (the cure), knows it, and whoever is unaware of it (the cure), he is unaware of it.” (the medicine) while those who are ignorant of it are unaware of it.”
[An-Nasai’î,Ibn Mãjah, Al-Hakim and Ibn Hibban].
Also, it is narrated in the Musnad (by imam Ahmad) and the Sunan (of At-Tirmidhî and Ibn Mäjah) that Abu Khuzamah said:
“I said, ‘O Messenger of AIIäh m, about the Ruqya (divine remedies – Islamic prayer formula) that we use, the medicine we take and the prevention we seek, does aII this change AIIäh’s appointed destiny?’ He said, ‘They are a part of AIIäh’s appointed destiny.
These Ahadith indicate there are causes for whatever occurs in this world and also removal of these causes.
The Prophet’s statement that there is a cure for every disease might include both the curable and the humanly incurable diseases, for Alläh may have hidden these types of cures from mankind and blocked their path to acquiring them. Alläh knows best. The Prophet a said that the disease ends when the proper cure is applied to it, indicating that there is an opposite for every creation and thus there is an antidote for every disease. The Messenger of Alläh a has stated that when the two opponents meet, meaning, the proper remedy and the disease, recover from the illness occurs. When the medicine is given in a dosage higher than what is needed, or when it is not the required medicine, it might lead the body to another type of disease. When the dosage is less than what is needed, it will not be sufficient to cure the disease. When the sick person and the disease are not treated with the suitable medicine, cure and recovery does not occur. Also, when the time is not suitable for the cure, or when the body is unable or unsuitable for the prescribed medicine, the cure will not be effective. When all circumstances are favorable, the cure will surely be effective. This is the best explanation available for these Ahadith.
On the other hand, these Ahadith might be specific, in that Alläh has not created a disease that can be humanly cured but has sent down a cure for it. This is similar to what Alläh said: